The Short Health Scale: A valid and reliable measure of health related quality of life in English speaking inflammatory bowel disease patients

The Short Health Scale: A valid and reliable measure of health related quality of life in English speaking inflammatory bowel disease patients

Journal of Crohn's and Colitis (2013) 7, 616–621 Available online at www.sciencedirect.com The Short Health Scale: A valid and reliable measure of h...

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Journal of Crohn's and Colitis (2013) 7, 616–621

Available online at www.sciencedirect.com

The Short Health Scale: A valid and reliable measure of health related quality of life in English speaking inflammatory bowel disease patients Edel McDermott, Denise Keegan, Kathryn Byrne, Glen A. Doherty, Hugh E. Mulcahy ⁎ Centre for Colorectal Disease, St Vincent's University Hospital/University College Dublin, Elm Park, Dublin 4, Ireland Received 1 June 2012; received in revised form 27 July 2012; accepted 28 July 2012

KEYWORDS Inflammatory bowel disease; Crohn's disease; Ulcerative colitis; Health related quality of life; Disease activity; Short Health Scale

Abstract Background: Health related quality of life in inflammatory bowel disease is influenced both by disease activity as well as by the psychosocial characteristics of the individual patient. The Short Health Scale (SHS) is a four-part visual analogue scale questionnaire using open-ended questions that are designed to assess the impact of inflammatory bowel disease on a health related quality of life. The four dimensions include bowel symptoms, activities of daily life, worry and general wellbeing. It has previously been validated in Swedish and Norwegian speaking patients. Aim: To evaluate the SHS in an English speaking inflammatory bowel disease population. Methods: Four hundred and ninety Crohn's disease and ulcerative colitis patients completed the SHS. Individual SHS items were correlated with Inflammatory Bowel Disease Questionnaire (IBDQ) dimensions and with disease activity to assess validity. Test–retest reliability was assessed in 38 patients who completed the Short Health Scale two weeks apart. Results: All four items correlated with corresponding IBDQ dimensions with correlation coefficients ranging from − 0.66 to − 0.74 (all p values b 0.001). In addition, total SHS scores correlated with total IBDQ scores in both Crohn's disease (− 0.836) and ulcerative colitis (0.797). There was a stepwise increase in Short Health Scale scores with increasing disease activity (all p values b 0.001). Reliability was confirmed with test–retest correlations ranging from 0.70 to 0.89 (all p values b 0.005). Conclusions: The Short Health Scale is a valid and reliable measure of health related quality of life in English speaking inflammatory bowel disease patients. © 2012 European Crohn's and Colitis Organisation. Published by Elsevier B.V. All rights reserved.

⁎ Corresponding author at: Department of Gastroenterology, St Vincent's University Hospital/University College Dublin, Elm Park, Dublin 4, Ireland. Tel.: + 353 1 2694533. E-mail address: [email protected] (H.E. Mulcahy). 1873-9946/$ - see front matter © 2012 European Crohn's and Colitis Organisation. Published by Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.crohns.2012.07.030

The Short Health Scale in English speaking IBD patients

1. Introduction Crohn's disease and ulcerative colitis are chronic relapsing, remitting and disabling disorders that have biological, psychological and socioeconomic implications for patients, their families and society. 1–4 The biological burden of inflammatory bowel disease (IBD) is frequently measured using disease activity scales. However, even a precise measurement of activity may reveal comparatively little about the overall health of patients with chronic disease states. 5 Rather, health related quality of life is a multidimensional construct that involves psychological and social, as well as physical domains. It evolved as an important health concept in the 1980s and instruments have since been developed to assess quality of life in patients with chronic diseases, including IBD. 5 Quality of life scales are frequently incorporated as secondary endpoints in clinical trials and are also used in clinical practice. Many early quality of life scales for chronic disease involved extensive questions relating to specific symptoms, social functions, limitation of activities and mental health. 6,7 Since then, shorter scales have been developed, 8 culminating in the Short Health Scale (SHS) for IBD patients. 9 This instrument was developed in Sweden and consists of four simple 100 mm visual analogue scales assessing symptom burden, activities of daily life, disease related worry and sense of general well-being. The questions were designed to be open ended, so that patients could take any or all aspects of their life that they felt were important to them into account when completing the questionnaire.9 It was initially designed as part of a network strategy to describe various aspects of the health concept 10 and was validated in Swedish speaking patients with ulcerative colitis 9 and Crohn's disease 11 and more recently in Norwegian IBD patients. 12 The aim of our study was to evaluate the SHS in English speaking IBD patients.

617 Table 1 Demographic and clinical details of the 490 study patients. Variable Disease Ulcerative colitis Crohn's disease Gender Male Female Age (year)(median [range]) Disease duration (year)(median [range]) Family history No family history First degree relative affected Smoking status a Non-smoker Smoker Education a Junior (education to 16 years) Leaving (education to 19 years) Third level education Previous surgery No Yes Current treatment with immune modulator No Yes Current treatment with biological agent No Yes Clinical disease activity Remission Mild disease activity Moderate disease activity

216 (44%) 274 (56%) 242 (49%) 248 (51%) 38 (16–89) 7 (0.1–49) 392 (80%) 98 (20%) 397 (82%) 90 (18%) 137 (28%) 139 (28%) 213 (44%) 357 (73%) 133 (27%) 356 (73%) 134 (27%) 412 (84%) 78 (16%) 267 (55%) 138 (28%) 85 (17%)

a

2. Materials and methods The study included 490 ambulatory IBD patients attending a specialised clinic in a Dublin University Hospital. Patients were approached in clinic and asked to participate in the study prior to their medical consultation. Five hundred and eight patients were approached of whom 505 agreed to participate (two patients with presbyopia were unable to participate because they did not have reading glasses at the clinic and a single patient, who was unable to read or write, was also unable to participate). Fifteen patients, whose questionnaires did not have evaluable SHS data, were also excluded, leaving a final study population of 490. The demographic and clinical details of the study population are shown in Table 1. Ethical approval for study was obtained from the St. Vincent's University Hospital Ethics Committee.

2.1. Questionnaires Quality of life was measured using the SHS (Fig. 1). The questionnaire was designed to be self-administered and patients were asked to place a mark on the 100 mm visual analogue scale that they thought was appropriate to their condition. Scores are presented for each dimension and were also added together to form a total, or overall, score.

Data on smoking and education were not available for all patients.

Quality of life was also determined using the 32-item Inflammatory Bowel Disease Questionnaire (IBDQ) that collects data on the four dimensions including bowel symptoms, social function, emotional function and systemic symptoms. 7 The Harvey–Bradshaw index was used to assess Crohn's disease activity 13 and the partial Mayo score to measure ulcerative colitis activity. 14 Crohn's disease remission was defined as a Harvey–Bradshaw score of 0–4, mild disease 5–8, and moderate≥ 9. Ulcerative colitis remission was defined as a Mayo score of 0–2, mild disease 3–5, and moderate≥ 6. The consulting physician assessed disease activity without knowledge of the questionnaire results. We assessed validity by correlating both individual SHS items and total SHS score with IBDQ dimensions and total score. To establish validity, the four individual SHS dimensions should correlate most closely with similar items in the IBDQ (concurrent validity) than with other dimensions (discriminant validity). 9 We also compared SHS scores in patients who were in remission and those who had mildly and moderately active IBD with the expectation that disease activity would influence a valid quality of life scoring system (known-groups comparison/

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E. McDermott et al. How severe are the symptoms you suffer from your bowel disease? Very severe No symptoms symptoms Do your bowel problems interfere with your activities in daily life? Interfere to a very high degree

Not at all

How much worry does your bowel disease cause? Constant worry

No worry

How is your general feeling of well being? Very good

Dreadful

Figure 1

The Short Health Scale questionnaire.

predictive validity). 15 Thirty-eight additional patients (15 Crohn's disease, 23 ulcerative colitis) who were in remission completed the SHS score two weeks apart to determine test– retest reliability.

was a stepwise increase in all SHS dimensions and total score with increasing disease activity.

2.2. Statistical analysis

Table 4 shows test–retest results for 38 IBD patients in remission. The SHS test and two-week retest scores were similar in all dimensions in both Crohn's disease and ulcerative colitis patients. In addition, there were close Spearman rank correlation coefficients and intraclass correlations between test–retest scores ranging from 0.64 to 0.91 in the four items and the total score.

Continuous data are presented as medians and interquartile ranges. Correlations between continuous data were analysed using Spearman's rank correlation coefficient (rs) and intraclass correlations. Differences in unpaired and paired groups were assessed using the Kruskal–Wallis test and Wilcoxon's signed rank test respectively. Statistical calculations were performed using the Statistical Package for the Social Sciences (SPSS 18.0; SPSS, Chicago, Illinois).

3. Results 3.1. Validity Table 2 shows correlations between the four SHS dimensions and their corresponding IBDQ items. Correlation coefficients for the “symptom burden”, “activities of daily life” and “general well being” dimensions ranged from −0.685 to −0.737 while the “disease related worry” subscale had slightly lower correlation coefficients of −0.682 and −0.662 for Crohn's disease and ulcerative colitis patients respectively. The individual SHS items were less closely associated with non-corresponding IBDQ dimensions, with correlation coefficients ranging between −0.475 and −0.695. Total SHS score also correlated with total IBDQ score in both Crohn's disease (−0.836) and ulcerative colitis (−0.797) patients. Correlations between disease activity scores and individual SHS dimensions ranged from 0.467 to 0.677 with the closest correlations found with “function” and “bowel symptom” subscales and the poorest correlation with the “disease related worry” subscale. Table 3 shows the association between disease activity and SHS scores. In those Crohn's disease and ulcerative colitis patients in remission, “disease related worry” score was higher than other dimensions. There

3.2. Reliability

4. Discussion We sought to identify a health related quality of life tool for clinical and research use that met specific requirements. Firstly, as advocated by experts in the field of survey design, 16,17 we considered it necessary for the questionnaire to be user friendly and have an unambiguous and standardised question format. Secondly, it was required to be applicable to all IBD patients while reflecting their individual perspectives. Finally, it needed to be both valid and reliable in our English speaking IBD population. The SHS is a simple and standardised four item visual analogue questionnaire that has previously been found to be quick and easy to administer. 9,11,12 Our patient population appeared to have little difficulty carrying out the survey, with the SHS questionnaire generally taking less than 1 min to complete. In relation to its applicability across a broad range of IBD patients, the tool uses open-ended questions that allow patients to rank what they consider important to themselves, an approach that was highlighted in the original description of the scale. 9 Thus, the questions are as applicable to a 25 year old, employed, sexually active male with Crohn's disease as they are to a 75 year old, retired, sexually inactive female with ulcerative colitis, reflecting each patient's individual perspective on their bowel symptoms, activities, disease related worry and general well-being. The open-ended and non-specific nature of the four questions may additionally make the SHS useful as a non-disease specific measure to allow

The Short Health Scale in English speaking IBD patients

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Table 2 Correlation between SHS (SHS) subgroups, IBDQ subgroups and disease activity in (above) 274 Crohn's disease patients and (below) 216 ulcerative colitis patients. Short Health Scale (SHS) Symptoms rs

Activities rs

Worry rs

Well-being rs

IBDQ bowel symptoms IBDQ social function IBDQ emotional function IBDQ systemic symptoms IBDQ total score Harvey–Bradshaw index

−0.728 − 0.678 − 0.517 − 0.679

− 0.575 −0.706 − 0.475 − 0.561

− 0.616 − 0.673 −0.682 − 0.688

− 0.656 − 0.607 − 0.484 −0.719

0.677

0.661

0.467

0.634

IBDQ bowel symptoms IBDQ social function IBDQ emotional function IBDQ systemic symptoms IBDQ total score Mayo score

−0.737 − 0.695 − 0.513 − 0.629

− 0.567 −0.70 − 0.510 − 0.587

− 0.525 − 0.564 −0.662 − 0.632

− 0.615 − 0.562 − 0.493 −0.685

0.674

0.667

0.534

0.552

Total score rs

−0.836 0.724

−0.797 0.707

Correlations between each SHS question and its corresponding IBDQ measure are printed in bold.

quality of life comparisons in patients with other diverse chronic medical conditions. The SHS has previously been found to be valid, reliable and responsive in both Swedish and Norwegian speaking patients, but has not been tested in English speaking populations. We found close associations between individual SHS items and their corresponding IBDQ dimensions, thus establishing convergent validity. In addition, individual SHS items tended to be more closely associated with their corresponding than non-corresponding IBDQ dimensions, establishing discriminant validity. Finally, all four dimensions and total SHS score correlated closely with disease activity in both Crohn's disease and ulcerative colitis patients, indicating that the baseline health status of patients

could be clearly distinguished using the SHS and establishing predictive validity. As we expected, the “disease related worry” dimension had the poorest correlation with disease activity. In addition, as in previous SHS studies, 9,11,12 we found worry to be relatively high in those patients in remission compared with the other subscales, indicating the complexity of biological, psychological, social and economic variables that may interact with each other to form an overall “worry” dimension for IBD patients. 18 We assessed the reliability of the SHS in a small group of patients in remission using surveys two weeks apart and found close and significant test–retest correlations in both Crohn's disease and ulcerative colitis patients. Although our results correspond with two-week test–retest Swedish data on

Table 3 Health related quality of life, measured with the SHS, and disease activity in (above) 274 Crohn's disease patients and (below) 216 ulcerative colitis patients. Variable

Crohn's disease activity (Harvey Bradshaw Index) Remission (n = 140)

Mild (n = 75)

Moderate (n = 59)

SHS symptoms 14 (5–32) 50 (26–70) 72 (59–86) SHS activities 12 (3–42) 51 (29–84) 84 (67–94) SHS worry 25 (10–56) 58 (45–79) 80 (52–96) SHS well-being 14 (5–33) 46 (23–66) 67 (51–85) SHS total score 80 (46–147) 209 (143–273) 290 (242–347) Remission defined as a Harvey–Bradshaw score of 0–4, mild disease 5–8, and moderate ≥ 9. Variable

SHS SHS SHS SHS SHS

symptoms activities worry well-being total score

p value b 0.001 b 0.001 b 0.001 b 0.001 b 0.001

Ulcerative colitis disease activity (Mayo score) Remission (n = 127)

Mild (n = 63)

Moderate (n = 26)

p value

17 (3–42) 15 (2–36) 30 (9–57) 16 (3–40) 101 (37–172)

61 (46–71) 60 (36–77) 61 (43–80) 49 (24–64) 231 (151–273)

82 (64–94) 89 (77–98) 86 (69–97) 65 (52–85) 325 (274–356)

b 0.001 b 0.001 b 0.001 b 0.001 b 0.001

Remission defined as a Mayo score of 0–2, mild disease 3–5, and moderate ≥ 6.

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E. McDermott et al.

Table 4 Test and two week retest results for (above) 15 Crohn's disease patients and (below) 23 ulcerative colitis patients in remission at both visits. Variable

Visit 1 SHS a

Visit 2 SHS a

p-value

rs

p value

ICC

b

Symptoms Activities Worry Well-being Total score

27 23 40 10 91

(1–47) (1–61) (14–68) (3–46) (77–210)

21 (9–33) 24 (4–42) 36 (17–56) 13 (4–46) 119 (48–147)

0.93 0.59 b 0.09 b 0.48 b 0.38 b

0.85 0.79 0.89 0.70 0.86

b 0.001 b 0.001 b 0.001 0.004 b 0.001

0.86 0.81 0.87 0.64 0.91

Symptoms Activities Worry Well-being Total score

26 20 36 18 121

(16–68) (6–64) (14–77) (10–48) (45–256)

30 (17–49) 30 (15–55) 40 (24–69) 34 (10–50) 125 (86–222)

0.95 b 0.42 b 0.70 b 0.08 b 0.73 b

0.77 0.80 0.86 0.88 0.84

b 0.001 b 0.001 b 0.001 b 0.001 b 0.001

0.78 0.84 0.89 0.83 0.89

rs. Spearman's rank correlation coefficient. ICC. Intraclass correlation. a Median (interquartile range). b Wilcoxon's signed rank test.

ulcerative colitis, 9 Jelsness-Jørgensen et al. found reliability to be lower when the test–retest period was extended to six months. 12 The reason for this is unclear, but it may be that subtle changes occur in patients' attitudes to stable disease over time that requires further investigation. Previous studies using an initial test and a further retest either at six months, or earlier if patients suffered a relapse, found the SHS to be responsive to changes in IBD activity. 9,11,12 However, we did not assess responsiveness as part of this particular study. From our point of view, one of the great strengths of the SHS is that it is simple and quick to perform, making it ideal for repeated measurements using a web-based, phone or other electronic device application. We therefore opted to perform an online longitudinal study with multiple assessments at frequent intervals to determine responsiveness in our patients, while at the same time assessing patient acceptability and satisfaction with the concept of intensive web-based IBD monitoring. This study is now in progress and preliminary results of the first 28 patients experiencing a change in disease activity over a three-month period have identified SHS changes similar to those of previous Swedish and Norwegian studies 9,11,12 (Hugh Mulcahy, personal communication). Health related quality of life is becoming an increasingly important component of IBD research and clinical care. 19,20 Our data, and those of others, 9,11,12 suggest that the SHS provides a simple, quick, valid and reliable measurement of health status in IBD patients and correlates well with other validated quality of life questionnaires. However, it is not known if a single question such as “How is your general feeling of wellbeing?” provides a more or less accurate measurement of actual wellbeing than a number of specific questions regarding individual quality of life dimensions. On the other hand, it is also unlikely that even a lengthy series of specific questions within four quality of life domains can effectively capture all the subtle elements of the broad and complex quality of life construct. Some of these answers might be obtained following a comprehensive biological, psychological, social, economic and epigenetic study to tease out some of the important factors that interact to give IBD patients their overall SHS quality of life score.

Conflict of interest None.

Acknowledgements The authors would like to thank Dr Henrik Hjortswang for permission to validate the SHS in English. Use of the Inflammatory Bowel Disease Questionnaire, authored by Dr. Jan Irvine et al., was made under licence from the McMaster University, Hamilton, Canada.

EMD and HEM designed the study, DK and KB contributed to data acquisition, EMD and HEM performed data analysis and data interpretation, EMD and HEM co-wrote the first draft of the paper, and DK, KB and GAD critically appraised the manuscript and contributed to additional manuscript writing.

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