Patients with irritable bowel syndrome in Swedish primary care

Introduction

Irritable bowel syndrome (IBS) is a chronic recurring gastrointestinal disorder quite commonly diagnosed in primary care [1–3]. However, there are deficient data on the rates of health care utilization in primary care by patients with IBS [4], [5]. An earlier Swedish study reported an IBS incidence rate of 2 per 1 000 person-years [1]. In studies from the UK and USA, incidence rates of 2–3 cases per 1 000 person-years have been reported [2], [6]. Other factors than gastrointestinal (GI) symptoms might also be important when it comes to seeking health care [7], [8]. IBS patients have been documented with a higher prevalence of stress and mental diagnoses, compared to the general population [3], [9], [10].

Research on IBS has so far mostly been based on hospital outpatients rather than primary care patients [11]. More research concerning consulting pattern, incidence, diagnosis, medication and treatment of patients with IBS in general practice is warranted [11]. Accordingly, in this study we have focused on computerized medical records of IBS patients in primary care.

Aim

The aim of this study was to estimate the consulting incidence of IBS and the consulting pattern for this patient population in a well defined primary care region.

Methods

All diagnosed cases with IBS (n=849) at three primary health care centres (PHC) in Linköping, Sweden, covering a total study population of over 40 000 inhabitants, were identified retrospectively through computerized medical records for a 5-year period. IBS cases were identified according to (International Classification of Diseases) ICD-10-P (code K-58-p), in the medical records. The cases were also checked 3 years prior to their IBS diagnosis to exclude IBS cases with a confirmed diagnosis before the period studied. Applying this criteria n=115 prevalent cases were excluded together with a further n=11 IBS cases with non-accessible medical record, thus giving a study group of n=723 IBS cases. Data comprise information (such as number of health care visits, reason for consulting and perceived complaints such as stress in daily life) from all GP consultations were the diagnosis IBS was registered in the medical records.

All data were stored in a common database and statistically analysed using the (Statistical Package for the Social Sciences) SPSS program (version 11.0). In the statistical analysis, differences were assessed by the chi-square method. IBS occurrence rates were calculated as incidence rates per 1 000 person-years. Logistic regression analysis was used to estimate the relative risks with 95% confidence intervals (CI) of different complaints as dependent variables associated with age and gender as the independent variables. This study was approved in 2002 by the Research Ethics Committee of the Faculty of Health Sciences, Linköping University, Sweden.

Results

The consultation incidence of IBS was 3.4 (95% CI 3.20–3.70) per 1 000 person-years; females: 4.6 (95% CI 4.16–4.97) and males: 2.3 (95% CI 2.01–2.59), see Figure 1. The incidence in females was more than double that of men in all age-groups except in the youngest age-group. The relative risk among females compared to males was 1.99 (95% CI 1.70–2.31).

Figure 1.  Consulting incidence rates per 1 000 person-years for female and male irritable bowel syndrome (IBS) cases in different age-groups.

Of all the IBS cases, 63% had abdominal discomfort documented as the main reason for consulting their GP and 31% had abdominal discomfort in combination with non-abdominal complaints and 6% had other discomforts recorded as the main reason for the consultation. No gender difference in these respects was found. 52% consulted their GP at an open surgery without an appointment. Planned consultations were more common (p<0.0001) among the elderly while consultations without an appointment were more common among the younger patients (p<0.0001). Some seasonal variation among the initial GP consultations was found, with peaks in the spring and autumn, although not statistically significant. For 24% of the IBS cases there were documented complaints of stress in daily life, especially among the gainfully employed (p<0.0001).

Discussion

Studies of incidence rates for IBS are quite rare, whereas prevalence studies in the general population based on surveys are available in several countries [1], [2], [5], [12–14]. The incidence rate found in this study, 3.4 per 1 000 person-years which increased with age, was slightly higher than what has been found in other comparable studies [1], [2], [6]. This increases with age and the overrepresentation of females found is in line with prevalence studies [7], [15], [16].

It has been noted that the reason for IBS patients to consult their GP is often related to fear of a serious illness [17]. In this study, the majority of the patients consulted without an appointment and had abdominal discomfort as sole consulting reason. Stress in everyday life was frequently recorded among the IBS patients, which is in accordance with other studies [3], [9], [10].

Medical records in primary care in Sweden are generally regarded as a good source of data on health care utilization. Computerized medical records have attracted more interest as an invaluable source of data for shedding light on diseases in primary care [18], [19] and studies with this approach have been performed [20], [21].

This study was supported by a grant from AstraZeneca R&D, Mölndal, Sweden. We also want to express our gratitude to the staff at the participating primary health care centres in Linköping.