Testing the reliability and validity of a clinically useful supportive care needs screening tool in the cancer population.

Background Fitch defines supportive care as “including the provision of physical, psychosocial, informational and spiritual needs during diagnostic, treatment, and follow up phases of cancer care. Supportive care embraces the full range of issues that emerge for an individual as the impact of cancer and treatment are felt and the person tries to deal with the situation”

Despite growing evidence of their benefit many types of supportive care are not routinely implemented in the clinical practice setting. Research of the cancer population indicates that there remains a high incidence of unmet supportive care need and that unmet needs are likely to adversely impact on outcomes. It is likely that many patients miss out because clinicians do not routinely asked about the patient’s supportive care needs and/or patients do not initiate discussion about their supportive care needs. Despite a number of supportive care screening tools available few are used routinely in clinical practice and there have been few attempts to translate research findings into sustainable clinical practice models.

A clinically useful Peter Mac Supportive Needs Screening Tool (SNST) was developed to be used routinely to identify supportive care needs of cancer patients in the ambulatory setting. The development of the tool followed a review of relevant literature and engagement of the multidisciplinary team to identify questions they thought reflected key referral criteria. As this was a new tool, following pilot testing which indicated clinician and patient satisfaction, information regarding the reliability and validity of the tool was required.

Objectives The aim of this project was to determine the reliability and validity of the Peter Mac Supportive Needs Screening Tool (SNST). The tool was tested in an ambulatory care radiotherapy centre in metropolitan Melbourne.

Primary objectives 1. To estimate the correlations between the three instruments (Peter Mac

SNST, BSI18 and SCNS) in their psychological domain scores. 2. To estimate the correlations between two instruments (Peter Mac

SNST and SCNS) in physical, sexuality and health­system and information domain scores.

3. To assess the repeatability of the Peter Mac SNST instrument.

Secondary To assess the association between each item, as well as the mean of the items, in the psychological domain of the Peter Mac SNST with the depression and anxiety scores in the BSI18.

Method Setting: The study was conducted in outpatient clinics at the Moorabbin site of the Peter MacCallum Cancer Centre (Peter Mac). Patients with cancer attending the Moorabbin site were selected because staff at this site have not been involved in the pilot testing of the Peter Mac SNST. This site provides radiotherapy treatment to patients and is not involved in providing chemotherapy or surgery to patients attending the centre increasing the homogeneity of the group.

The Tools: The Supportive Needs Screening Tool (Peter Mac SNST) was a 30 question patient­completed tool that has been grouped into five domains, the physical, psychological, social, information, and spiritual needs. The Peter Mac SNST is mostly a “yes/no” format. The Peter Mac SNST was not intended to measure change in intensity of needs.

The short form of Supportive Care Needs Survey (SCNS) was used to assess patients’ unmet needs. It has 59 items and 5 subscales: psychological, health information, physical and daily living needs, patient care and support needs and sexuality. The long form displays high internal consistency and construct validity.

The Brief Symptom Inventory – 18 (BSI­18) was an 18 item 0­4 rating scale that has been validated in the cancer population, and provides three sub­ scores – somatization, depression and anxiety with values specific to gender as well as an overall distress score.

There were also project specific questions at the end of the Peter Mac Screening Tool and the SCNS which included questions regarding the tools, whether the questions are understood, are able to be answered and whether patients would feel comfortable with completing the questionnaires again.

Design: This was a cross­sectional study. For the test­re­test, participants completed the first assessment while waiting for their appointment and completed the second stage assessment at home 72 hours later and returned this by post.

To evaluate construct validity patients completed the three assessment tools at the same time either whilst on site waiting for an appointment or at the 72 hour follow­up. The questionnaire pack contained the Peter Mac SNST, the SCNS and the BSI­18 presented in a random order.

Sample A sample of 200 was required. There were two arms of the study design. This was to identify if there was any bias introduced because of the order of completing the tools.

Results

Two hundred people agreed to participate in the project, and from this group a total of 159 participants completed the tools at the two time points. The cancer diagnosis of the people who agreed to participate were:

• 104 breast • 39 Prostate • 20 Gastrointestinal • 12 Lymphoma, myeloma, leukaemia • 9 Gynaecological • 9 Lung • 7 Other

Of the participants who did not complete the tools at the two time points (41 of 200)

(20%) there was no specific pattern as to which tool was not completed:

– 18 Peter Mac Screening Tools when completed alone

– 22 Peter Mac Screening Tools when completed with other 2 tools

– 26 Supportive Care Needs Surveys

– 27 Brief Symptom Inventory

In order to investigate the validity of the SNST Psychological Domain, total scores

were calculated for the 12 items in the SNST Psychological Domain, the 18 items in

the BSI­18, and the 22 items in the SNCS Psychological Domain. The domain

scores were then assessed for normality and any potential response biases or

differential functioning by different demographic sub­groups. Finally, the domain

scores were assessed in relation to criterion measures to determine the validity of the

scales.

According to published guidelines for scoring the BSI­18 and the SCNS, total scores

were calculated by summing the answers for each question.

To calculate the total score for the SNST Psychological Domain, responses to each

question were summed and then divided by the number of items to achieve an

average score for the domain. This method effectively results in each patient having

a proportion of need, providing an easily interpretable measure of the depth of need

that each patient has. This also allows respondents to be easily compared across

domains to quickly and easily determine which areas patients are most in need of

supportive care assistance.

The SNST Psychological Domain score displays a mild Poisson distribution, with

values spanning almost the full range of possible scores from 0 to 0.92 (possible

value range 0­1.0; see Figure 2 for distribution; see Table 13 for means and standard

deviations; see Appendix H.1 for item distributions). As the Psychological Domain

score equates to a count of the number of needs a patient has, a Poisson distribution

is expected. Accordingly, non­parametric tests will be used to assess relationships

between the different validation measures.

Primary Objective 1 ­ Construct Validity of the Psychological Domain

A fundamental assumption made during the development of the SNST was that the

tool would be used as a preliminary screening to identify patients who might have

need of additional supportive care assistance. It was therefore the aim of the tool to

be correlated with other previously validated measures of supportive care needs,

such as the SCNS, and in the case of the psychological domain for the SNST to be

correlated with measures of psychological pathology. As a measure of psychological

pathology or symptomology, the BSI­18 was also included in the questionnaire

battery as a validation measure for the SNST Psychological Domain. Therefore, it is

anticipated that people with high scores on the SNST, indicating a high need of

supportive care assistance, will also obtain high scores on the BSI­18 and the SCNS

Psychological Domain.

In order to investigate the potential presence of any order effects, a multivariate

analysis of variance was conducted on the 3 psychological domain scores (SNST

Psychological Domain, BSI­18, and the SCNS Psychological Domain) for the two

arms of the test administration. There was no significant difference in the mean

scores of the SNST Psychological Domain, the BSI­18, or the SCNS Psychological

Domain for the different arms. The order of test administration, SNST first and 3

tools second or the 3 tools first and the SNST second, did not result in significantly

different mean scores on the psychological domains of the 3 tools. Accordingly,

further analyses of the psychological domains were conducted for both arms

together.

A series of Spearman’s correlations were conducted to determine if any relationship

existed between the scores on the 3 different tools.

1.1 SNST Psychological Domain and BSI­18

A strong positive relationship was found between the SNST Psychological Domain

and the BSI­18 Total Score (Rho=0.711, p<0.001). Patients who scored highly on

the BSI­18 also tended to score highly on the SNST Psychological Domain (see

Figure 1).

Figure 1

Scatterplot of SNST Psychological Domain Score with BSI­18 Total Score

60 50 40 30 20 10 0

BSI_Total

1.00

0.80

0.60

0.40

0.20

0.00

SNST

_3_P

SYCH_M

ean1

2

SNST First

3 Tools First

SNST First

3 Tools First

Arm

R Sq Linear = 0.673

R Sq Linear = 0.567

1.2 SNST Psychological Domain and SCNS Psychological Domain

A moderately strong positive relationship was found between the SNST

Psychological Domain and the SCNS Psychological Domain (Rho=0.562, p<0.001).

Patients who scored highly on the BSI­18 also tended to score highly on the SNST

Psychological Domain (see Figure 2).

Figure 2

Scatterplot of SNST Psychological Domain Score with SCNS Psychological Domain

Score

1.00 0.80 0.60 0.40 0.20 0.00

SCNS_Psych_summ22_bi

1.00

0.80

0.60

0.40

0.20

0.00

SNST

_3_P

SYCH_M

ean1

2

SNST First

3 Tools First SNST First

3 Tools First

Arm

R Sq Linear = 0.514

R Sq Linear = 0.235

1.3 SCNS Psychological Domain and BSI­18

A strong positive relationship was found between the SCNS Psychological Domain

and the BSI­18 Total Score (Rho=0.706, p<0.001). Patients who scored highly on

the BSI­18 also tended to score highly on the SCNS Psychological Domain (see

Figure 3).

Figure 3

Scatterplot of SCNS Psychological Domain Score with BSI­18 Total Score

60 50 40 30 20 10 0

BSI_Total

1.00

0.80

0.60

0.40

0.20

0.00

SCNS_

Psych_

summ22_b

i

SNST First

3 Tools First SNST First

3 Tools First

Arm

R Sq Linear = 0.558

R Sq Linear = 0.417

1.4 Sensitivity of the SNST as a Screening Tool

The SNST was designed to be used as a screening tool to help clinicians identify

patients who may need further assistance or additional supportive care. In an effort

to ensure that all patients who may have a need are able to speak to a clinician so

that the patient’s needs can be explored to determine the extent, importance and

immediacy of the supportive care need, to determine whether the provision of

information will satisfy the need or whether referral to an ancillary is required. The

SNST must be able to detect any potential need, not only cases of clinical pathology.

The BSI­18 was designed as a clinical tool to help identify patients with clinical

symptoms of Anxiety, Depression, and Somatisation. Significant pathology must be

present in order for a patient to be considered a case, however patients without such

a severe level of clinical pathology may simply require less stringent interventions to

alleviate their symptoms. Therefore, it is anticipated that the SNST will identify more

patients as ‘cases’ (requiring further interview with a clinician) than the BSI­18,

although the SNST should display similar levels of sensitivity in identifying ‘cases’ as

the SCNS ‘No Need/Some Need’ dichotomy.

As expected, the SNST correctly classified 96% of cases identified by the BSI­18 (25

out of 26), and 85% of cases identified by the SCNS (94 out of 111). The SNST is a

highly sensitive tool for identifying patients with potential psychological or emotional

needs.

Table 1

Sensitivity of the SNST Psychological Domain Compared to the BSI­18 and the

SNST Psychological Domain

No Need (answered 'No' to all

questions)

Some Need (answered 'Yes' to at least 1 question)

BSI­18 Non­Case %(n) 32.65% (48) 67.35% (99) Case %(n) 3.85% (1) 96.15% (25)

SCNS Psychology Domain No Need %(n) 50.82% (31) 49.18% (30) Some Need %(n) 15.32% (17) 84.68% (94)

SNST

Primary Objective 2 – Construct Validity of the Physical, Sexuality,

Health­System, and Information Domains

2.1 SNST Physical Domain and SCNS Physical Domain

In order to investigate the potential presence of any order effects, a multivariate

analysis of variance was conducted on the 2 physical domain scores (SNST Physical

Domain, and the SCNS Physical Domain) for the two arms of the test administration.

A significant difference was found in the mean scores of the SCNS Physical Domain

for the different arms (F(1)=3.929, p=0.049). Patients who completed the 3 tools first

and the SNST second scored significantly higher on the SCNS Physical Domain than

patients who completed the SNST first and the 3 tools first second. Accordingly,

further analyses of the physical domains were conducted for each arm separately.

A strong positive relationship was found between the SNST Physical Domain Score

and the SCNS Physical Domain Score for Arm 1 (3 tools first: Rho=0.697, p<0.001)

and for Arm 2 (SNST first: Rho=0.651, p<0.001). Patients who scored highly on the

SCNS Physical Domain also tended to score highly on the SNST Psychological

Domain (see Figure 4), however the relationship was slightly stronger when patients

completed the 3 tools first.

Figure 4

Scatterplot of SNST Physical Domain Score with SCNS Physical Domain Score

1.00 0.80 0.60 0.40 0.20 0.00

SCNS_Phys_summ7_bi

0.60

0.50

0.40

0.30

0.20

0.10

0.00

SNST

_3_P

HYS

_Mean2

6

SNST First

3 Tools First SNST First

3 Tools First

Arm

R Sq Linear = 0.473

R Sq Linear = 0.42

2.2 SNST Sexuality Domain and SCNS Sexuality Domain

In order to investigate the potential presence of any order effects, a multivariate

analysis of variance was conducted on the 2 sexuality domain scores (SNST

Sexuality Domain, and the SCNS Sexuality Domain) for the two arms of the test

administration. There was no significant difference in the mean scores of the SNST

Sexuality Domain (F(1)=0.068, p=0.795) and the SCNS Sexuality Domain

(F(1)=0.230, p=0.632) for the different arms. The order of test administration, SNST

first and 3 tools second or the 3 tools first and the SNST second, did not result in

significantly different mean scores on the sexuality domains of the 2 tools.

Accordingly, further analyses of this domain were conducted for both arms together.

A weak to moderate positive relationship was found between the SNST Sexuality

Domain and the SCNS Sexuality Domain (Rho=0.411, p<0.001). Patients who

scored highly on the SCNS Sexuality Domain also tended to score highly on the

SNST Sexuality (see Figure 5).

Figure 5

Scatterplot of SNST Sexuality Domain Score with SCNS Sexuality Domain Score

1.00 0.80 0.60 0.40 0.20 0.00

SCNS_Sex_summ3_bi

1

0.8

0.6

0.4

0.2

0

SNST

_3_S

EX_Q

13hD

ecr

SNST First

3 Tools First SNST First

3 Tools First

Arm

R Sq Linear = 0.111

R Sq Linear = 0.25

2.3 SNST Support Domain and SCNS Health­System Domain

In order to investigate the potential presence of any order effects, a multivariate

analysis of variance was conducted on the 2 health­system/support domain scores

(SNST Support Domain, and the SCNS Health­System Domain) for the two arms of

the test administration. There was no significant difference in the mean scores of the

SNST Support Domain (F(1)=0.719, p=0.398) and the SCNS Health­System Domain

(F(1)=0.014, p=0.907) for the different arms. The order of test administration, SNST

first and 3 tools second or the 3 tools first and the SNST second, did not result in

significantly different mean scores on the health­system/support domains of the 2

tools. Accordingly, further analyses of this domain were conducted for both arms

together.

A weak positive relationship was found between the SNST Support Domain and the

SCNS Health­System Domain (Rho=0.265, p<0.001). Patients who scored highly on

the SCNS Health­System Domain also tended to score highly on the SNST Support

Domain (see Figure 6).

Figure 6

Scatterplot of SNST Support Domain Score with SCNS Health­System Domain

Score

1.00 0.80 0.60 0.40 0.20 0.00

SCNS_Supp_summ12_bi

0.70

0.60

0.50

0.40

0.30

0.20

0.10

0.00

SNST

_3_S

UPP

_Mean1

0

SNST First

3 Tools First SNST First

3 Tools First

Arm

R Sq Linear = 0.008

R Sq Linear = 0.116

2.4 SNST Information Domain and SCNS Information Domain

In order to investigate the potential presence of any order effects, a multivariate

analysis of variance was conducted on the 2 information domain scores (SNST

Information Domain, and the SCNS Information Domain) for the two arms of the test

administration. There was no significant difference in the mean scores of the SNST

Information Domain (F(1)=0.265, p=0.608) and the SCNS Information Domain

(F(1)=0.027, p=0.869) for the different arms. The order of test administration, SNST

first and 3 tools second or the 3 tools first and the SNST second, did not result in

significantly different mean scores on the information domains of the 2 tools.

Accordingly, further analyses of this domain were conducted for both arms together.

A weak to moderate positive relationship was found between the SNST Information

Domain and the SCNS Information Domain (Rho=0.405, p<0.001). Patients who

scored highly on the SCNS Information Domain also tended to score highly on the

SNST Information Domain (see Figure 7).

Figure 7

Scatterplot of SNST Information Domain Score with SCNS Information Domain Score

1.00 0.80 0.60 0.40 0.20 0.00

SCNS_Info_summ15_bi

1.00

0.80

0.60

0.40

0.20

0.00

SNST

_3_INFO

_Mean2

3

SNST First

3 Tools First SNST First

3 Tools First

Arm

R Sq Linear = 0.113

R Sq Linear = 0.301

Primary Objective 3 – Reliability Analysis of the SNST 3.1 Test­Retest Reliability/Repeatability Analysis

In order to investigate the test­retest reliability of the SNST, the tool was

administered twice, the first administration was at the hospital, and a second

questionnaire was given to patients to take home. Patients were instructed to

complete the second questionnaire and return within 7 days via a reply paid

envelope. Accordingly, correlations between questionnaire administration 1 and

questionnaire administration 2 were conducted to determine whether patients felt the

same, and responded in the same fashion after a 1 week delay.

Moderate to strong positive correlations were found between the two test

administrations of the questions in the SNST Psychological Domain, with

Spearman’s Rho coefficients ranging from 0.328 to 0.758. All correlations were

significant at p<0.001 level (see Table 2). Overall, patients responded to the

questions in the Psychological Domain in a consistent manner over time. This is

reflective of the long­term and ongoing nature of psychological and emotional

problems associated with depression and anxiety.

Table 2

Test­Retest Correlation Co­efficients for the Questions in the SNST Psychological

Domain. Spearman's Rho

Correlation p­value

Psychological 14 a) During the past two weeks have you felt sad, flat or depressed most of the time? 0.527 0.000 14 b) During the past two weeks have you felt a loss of interest or pleasure in things that you usually enjoy? 0.530 0.000 14c) During the past two weeks have you felt a lot of worry or anxiety? 0.484 0.000 14d) During the past two weeks have you found it difficult to take your mind off worrying thoughts? 0.445 0.000 14 e) During the past two weeks have you experienced feelings of sudden panic or fear? 0.543 0.000 14 f) During the past two weeks have you felt very restless, or constantly needed to be on the move? 0.552 0.000 14 g) During the past two weeks have you felt generally slowed down or sluggish? 0.328 0.000 14 h) During the past two weeks have you had difficulty concentrating or making decisions? 0.591 0.000 14 i) During the past two weeks have you had thoughts about giving up? 0.413 0.000 15) Has there ever been a time whey you felt sad or depressed for more than a few weeks? 0.502 0.000 16) Have you ever had any treatment for psychological / emotional concerns 0.758 0.000 17) Are you currently receiving treatment for psychological / emotional concerns? 0.619 0.000

Many moderate to strong positive correlations were found between the two test

administrations of the questions in the SNST Physical Domain, however some weak

correlations were also found. Spearman’s Rho coefficients ranged between 0.185

and 0.744, and all correlations were significant at p<0.001 level (see Table 3).

Closer examination of the questions revealed that questions with weaker correlations

tended to relate to more transient issues of physical needs which may present or be

alleviated within shorter periods of time, such as vomiting, while questions with

stronger correlations tended to relate to longer term physical issues, such as having

difficulty hearing or experiencing weight loss.

Table 3

Test­Retest Correlation Co­efficients for the Questions in the SNST Physical Domain. Spearman's Rho

Correlation p­value

Physical 4. Do you any difficulty with speaking or communicating

5. Do you have difficulty in concentrating and remembering things? 0.511 0.000 6. Do you have difficulty hearing? 0.744 0.000 7. Do you have any difficulty with seeing? 0.335 0.000 9. Do you use any type of health or mobility aid? 0.425 0.000 11. In the last 3 months have you lost more than 5 kg (1 stone) in weight? 0.711 0.000 12. During the past two weeks did pain interfere with your activities? 0.459 0.000 13 a) During the past two weeks have you been feeling sick or nauseous 0.488 0.000 13 b) During the past two weeks have you been vomiting? 0.185 0.000 13 c) During the past two weeks have you had a headache or dizziness? 0.423 0.000 13 d) During the past two weeks have you had lack of appetite? 0.455 0.000 13 e) During the past two weeks have you had fatigue or tiredness or lack of energy? 0.434 0.000 13 f) During the past two weeks have you had any difficulty swallowing? 0.355 0.000 13 g) During the past two weeks have you been feeling short of breath 0.563 0.000 13 i) During the past two weeks have you had sleep problems (eg falling asleep or sleeping too much) 0.517 0.000 13 j) During the past two weeks have you had difficulty with your bowels 0.536 0.000 13k) During the past two weeks have you had difficulty passing water 0.306 0.000 13 l) During the past two weeks have you had problems with your mouth 0.278 0.000 13 m) During the past two weeks have you had problems with your skin 0.424 0.000 13 n) During the past two weeks have you had problems with swelling of your arms or legs 0.459 0.000 18 a) During the past two weeks did you need help with dressing? 0.604 0.000 18b) During the past two weeks did you need help with showering / bathing 0.590 0.000 18 c) During the past two weeks did you need help with toileting

18 d) During the past two weeks did you need help with cooking / eating 0.555 0.000 18 e) During the past two weeks did you need help with using stairs 0.218 0.000 18 f) During the past two weeks did you need help with shopping or looking after your home 0.540 0.000

*All patients answered 'No' when 3 tools administered together

*All patients answered 'No' at both administrations

Many weak to moderate strength positive correlations were found between the two

test administrations of the questions in the SNST Health­System & Information

Domain. Some very weak correlations were also found. Spearman’s Rho

coefficients ranged between 0.101 and 0.621, and all correlations were significant at

p<0.001 level (see Table 4). Closer examination of the questions again revealed that

questions with weaker correlations tended to relate to more transient issues of

health­system and information needs which may present or be alleviated within

shorter periods of time, such as requiring medical certificates, while questions with

stronger correlations tended to relate to longer term physical issues, such as

relaxation, meditation, and worship/prayer.

Table 4

Test­Retest Correlation Co­efficients for the Questions in the SNST Health­System &

Information Domain. Spearman's Rho

Correlation p­value

Health­System & Information Would you like more information about: 29 a) Who is in your treatment team and what they do? 0.403 0.000 29b) Your diagnosis 0.318 0.000 29c) your treatment choices 0.315 0.000 29d) understanding your medicines 0.422 0.000 29e) possible side­effects and discomforts during and after treatment 0.401 0.000 29f) prognosis 0.345 0.000 29g) using complementary therapies 0.400 0.000 29h) palliative care services 0.451 0.000 29 i) aftercare: what happens at the end of treatment 0.277 0.000 30 a) help getting to and from hospital 0.195 0.000 30 b) travel assistance or reimbursement for rural patients 0.438 0.000 30c) accommodation assistance for you / family during your treatment 0.101 0.000 30d) home care and other in home assistance 0.170 0.000 30 e) support for children or dependent family members whilst you are having treatment 0.363 0.000 30 f) medical certificates or employment related issues 0.108 0.000 30 g) financial assistance including sickness benefits, social security. 0.460 0.000 31 a) Diet 0.484 0.000 31 b) activity recommendations 0.456 0.000 31 c) counselling 0.369 0.000 31d) relaxation 0.501 0.000 31d) meditaition 0.601 0.000 31 e) worship / prayer 0.621 0.000 31f) services to help your family 0.347 0.000

Many moderate to strong positive correlations were found between the two test

administrations of the questions in the SNST Support Domain. Some very weak

correlations were also found. Spearman’s Rho coefficients ranged between 0.081

and 0.757, and all correlations were significant at p<0.001 level (see Table 5).

Closer examination of the questions revealed that there was one question with

almost no correlation which related to having someone to talk to about feelings and

concerns. It would be expected that this question is not transient; having a friend or

family member with whom to talk does not change within a period of one week. This

finding raises possible questions about whether the patient feels comfortable talking

about their feelings and concerns, regardless of whether someone is available to talk

to. This result is interesting and requires further investigation to clarify the

interpretation of this question, and/or why patients are experiencing such a change in

such a short period of time.

Further, examination of the questions with stronger correlations revealed that many

other questions for which the response would be unlikely to change within the period

of one week displayed only moderate correlations. For example, “Have you recently

experienced the loss of a loved one?” displayed only a moderate strength

relationship (Rho=0.577). It would be very unusual for half of the sample to have lost

a loved one in the space of one week between test administrations.

Table 5

Test­Retest Correlation Co­efficients for the Questions in the SNST Support Domain. Spearman's Rho

Correlation p­value

Support 23) Are there other adults currently living with you? 0.567 0.000 24) Do you currently care for children or dependent adults 0.757 0.000 25 a) Have you recently been troubled by problems with accommodation or your living arrangements? 0.556 0.000 25 b) Have you recently been troubled by serious health problems? 0.295 0.000 25 c) Have you recently been troubled by the loss of a loved one? 0.577 0.000 25 d) Have you recently been troubled by significant financial difficulties? 0.530 0.000 25 e) Have you recently been troubled by significant relationship difficulties? 0.556 0.000 26) Have you been having difficulties coping with the treatment? 0.241 0.000 27) Is there someone who will be available to give you practical assistance during your treatment? 0.190 0.000 28) Is there someone that you can talk to about your feelings or concerns? 0.081 0.000

A weak positive correlation was found between the two test administrations of the

question in the SNST Sexuality Domain (Rho=0.346, p<0.001; see Table 6). This

may be indicative of the relatively transient nature of sexual activity, and the specific

instruction to think about the past two weeks.

Table 6

Test­Retest Correlation Co­efficients for the Question in the SNST Sexuality Domain. Spearman's Rho

Correlation p­value

Sexuality 13h) During the past two weeks have you had decreased sexual interest or activity. 0.346 0.000

Overall, the majority of questions in the SNST displayed very good test­retest

reliability, and many of those with poor test­retest reliability could reasonably be

expected to be unstable over short periods of time. The Psychological Domain

displayed strong test­retest reliability, supporting the contention that the questions in

this domain tap into the relatively stable and psychological and emotional aspects of

patients supportive care needs. The Physical Domain, Health­System & Information

Domain, and Sexuality Domain all reflect test­retest reliability in accordance with the

types of questions in each domain. Questions about short­term, transient issues and

needs display weaker test­retest reliability than questions about longer­term, stable

issues and needs. The Support Domain has produced unexpected results, with the

majority of correlations not as strong as expected in relation to the level of stability of

the issue of need. This raises several questions of potential utility of these questions

and should therefore be investigated further.

3.2 Internal Consistency Reliability Analysis

In order to investigate the suitability of the SNST subscales, separate Reliability

Analyses were conducted on each of the SNST Domain subscales, with the

exception of the Sexuality Domain as it comprises only one item (See Table 1 for

Kuder­Richardson 20 values; see Appendix for results of all reliability analyses).

The resulting reliability analysis on the 12 items of the SNST Psychological Domain

revealed strong internal consistency with a Kuder­Richardson 20 coefficient of 0.852

(see Appendix for results of reliability analysis). A Kuder­Richardson 20 value this

high indicates that there are substantial inter­correlations among the items.

Examination of the inter­item correlations revealed strong correlations between

following four items ‘During the past 2 weeks have you: ‘felt sad, flat or depressed

most of the time?’, ‘felt a loss of interest or pleasure in things that you usually

enjoy?’, ‘felt a lot of worry or anxiety?’, and ‘found it difficult to take your mind off

worrying thoughts?’ (see Table for intercorrelations). The item ‘felt a loss of interest

or pleasure in things that you usually enjoy?’ also had the strongest corrected item­

total correlation (r=0.742), indicating that this item was adding the least information to

the scale over and above that contributed by the other scale items.

The 24 items of the SNST Physical Domain also had good internal consistency with a

Kuder­Richardson 20 coefficient of 0.804 (see Appendix for results of reliability

analysis), however the simple fact of having such a large number of items increases

the internal consistency of the scale regardless of the intercorrelations between the

items. Examination of the inter­item correlations revealed only a few moderate

strength relationships, however there were only weak to no relationship between

most of the items.

The ten Health­System and Support Domain items displayed poor internal

consistency with a Kuder­Richardson 20 coefficient of 0.530 (see Appendix F.4 for

results of reliability analysis). Examination of the inter­item correlations revealed that

most of the items were not related with Pearson’s r coefficients less than 0.1.

However, some weak relationships were found between the item ‘Are there other

adults currently living with you?’ and the item ‘Is there someone who will be available

to give you practical assistance during your treatment?’ (r=0.443), and also with the

item ‘Is there someone that you can talk to about your feelings or concerns?’

(r=0.319). A moderate strength relationship was also found between then items ‘Is

there someone who will be available to give you practical assistance during your

treatment?’ and ‘Is there someone that you can talk to about your feelings or

concerns?’ (r=0.627). Examination of the corrected item­total correlations revealed

that the item ‘Have you been having difficulties coping with your treatment?’ had

almost no relationship with the total of all the other items (r=0.093), and if removed

from the scale would increase the Kuder­Richardson 20 coefficient to 0.564.

The 23 Information Domain items displayed very strong internal consistency with a

Kuder­Richardson 20 coefficient of 0.919 (see Appendix F.4 for results of reliability

analysis). Again, such a high value is expected with such a large number of items in

the scale. Examination of the inter­item correlations revealed many moderate to

strong correlations between the items, indicating that many of the items are tapping

into similar aspects of the information needs of cancer patients. Examination of the

corrected item­total correlations revealed moderate strength relationships between

each individual item and the total of all other items combined, indicating that each

item, while related to the other items in the subscale, also provided a unique

contribution to the total score over and above that provided by the other items in the

scale.

Table 2

Internal Consistency estimates for the SNST Domains

Domain Number of items

Kuder­Richardson 20 Co­efficient

Psychological 12 0.852 Physical 24 0.804 Health­System & Support 10 0.530 Information 23 0.919

Scale Evaluation of the SNST

As the SNST is a newly developed tool designed to have 5 subscales, the underlying

structure of the SNST should be examined to determine if there really are 5

subscales as anticipated, or if the items in the scale actually display a different

underlying dimensionality. Factor Analysis should be conducted to investigate and

confirm the appropriateness of the subscales and the underlying structure.

Guidelines for the conduction of factor analysis specify that the minimum requirement

for the subject to variable ratio should be at least 5:1. Due to the relatively small

sample size of the current study compared to the large number of items in the SNST,

factor analysis could not be conducted in the present study as the minimum

requirement for subject to variable ratio has not been met. Future research should

aim to obtain sample large enough to conduct factor analysis in order to confirm the

assumed dimensionality of the SNST.

Implications The Supportive Needs Screening Tool is a clinically useful evidence­based tool that can be used to help identify patients who are at high risk of adverse psychological events. The tool is a patient completed form that the clinician can use as a basis for a focused discussion on the supportive care needs of a cancer patient. The tool helps facilitate the implementation of the NHMRC supportive care guidelines.

There has been intrastate, interstate and international interest in the Screening Tool. Peter Mac has received requests for a copy of the SNST from: • Cancer and Palliative Care, Department of Human Services, Vic • Project Officer, Western & Central Melbourne Integrated Cancer Service,

Vic • Nurse Unit Manager, Sutherland Day Oncology Unit, Warringal Private

Hospital • Breast Care Clinical Nurse Consultant; Maroondah Hospital • Breast Care Nurse Consultant, Epworth Hospital • Clinical Health Psychologist, Townsville Hospital • Respiratory Cancer Nurse, WA • Project Coordinator, Cancer Screening Services Unit, Population Health

Branch Queensland Health • Senior Project Officer, National Breast Cancer Centre, NSW • Cancer care Coordinator ­ chemotherapy St Vincents Hospital,

Darlinghurst • Breast Cancer Nurse Coordinator; Northern Sydney Central Coast Health • Breast Cancer Care Coordinator, Sydney South Western Area Health

Service

• Occupational Therapist in Cancer Services Austin Health • Psychiatrist from the Philippines. • The continuing education department of the hospital Links der Weser in

Bremen, Germany.