The burden of coeliac disease The perspectives of patients, health care system and society

Coeliac disease is heavily underdiagnosed and delay in diagnosis is typically several years. Untreated symptomatic disease is associated with increased morbidity, much of which can be prevented or reversed by treatment with a gluten-free diet in symptomatic patients. Whether a similar health gain can be achieved in screen-detected patients remains unclear. It has been suggested that undiagnosed coeliac disease causes an increased burden on the health care system as consumption of health care services might be increased among undiagnosed patients but be reduced on treatment. The aims of this study were to gain a comprehensive understanding of the burden of illness related to coeliac disease from the standpoint of affected individuals, the health care system and society, and to ascertain the impact of treatment with a gluten-free diet on this burden.

This dissertation comprised four prospective studies. In study I, health-related quality of life was evaluated with the Psychological General Well-Being (PGWB) questionnaire and the results compared to those of 110 adult non-coeliac controls at diagnosis and in the follow-up. The patients were asked to grade their subjective health status and concern about their heath in general. Study II assessed patients’ thoughts of coeliac disease, how the diagnosis was established, and treatment with a gluten-free diet. In addition, they indicated their special wishes or needs related to the disease. Initial body mass index (BMI) and the impact of a gluten-free diet on it, in addition to items explaining favourable or poor BMI outcome were assessed in study III. BMI values at diagnosis and on dietary treatment were compared to those of a random sample of the general population during the same periods. Study IV measured use of health care services, consumption of pharmaceutical agents and number of days of sickness absence from work in the years prior to and following the diagnosis to establish the possible effect of dietary treatment on these parameters. The number of consultations with a physician and days of sickness absence were compared to those in a sample of the general population.

The study involved 698 newly-detected adult coeliac disease patients, who were divided into three study groups according to clinical presentation: i) gastrointestinal symptoms and signs, ii) extraintestinal symptoms, and iii) screen-detected patients among whom a sub-group of asymptomatic patients was also analysed separately (I-III). Participants completed paired study questionnaires at diagnosis and after one year from the initial appointment. The results of studies I-III showed that quality of life was reduced in untreated patients but improved on a gluten-free diet and did not differ from that among the controls after one year. Dietary treatment resulted in similar health gain in all study groups irrespective of clinical presentation. Perceptions of health improved correspondingly and patients in all groups reported a positive general attitude towards the disease and dietary treatment. Only screen-detected asymptomatic patients reported no such positive effect. Their PGWB scores were comparable to those of the controls both at diagnosis and on a gluten-free diet, but concern for health increased after being diagnosed. Study III showed that even though 39% of coeliac disease patients were overweight at diagnosis, BMI in the coeliac group was lower than that in the general population both at diagnosis and after one year on treatment. Treatment with a gluten-free diet induced favourable changes in BMI equally in all study groups and also in asymptomatic patients. Prior to diagnosis, consumption of health care services and on-demand medication was increased, but was reduced during one year on treatment (IV). Compared to the general population, patients made more visits to a physician prior to but not post diagnosis. No excess in sickness absence was noted.

This study demonstrated that the burden of illness related to coeliac disease affects similarly both symptom- and screen-detected patients. Improved quality of life and health status and changes towards normal BMI can be achieved by dietary treatment. However, screen-detected asymptomatic patients show no such beneficial effects of treatment. Additionally, the burden to the health care system caused by undetected coeliac disease was diminished after implementation of a gluten-free diet. The results indicate that patients, health care system and, indirectly, society benefit from the early detection and treatment of coeliac disease. Further studies are needed to promote earlier diagnosis and to establish optimal strategies in the management of coeliac disease.