The impact of comorbid chronic conditions on quality of life in type 2 diabetes patients

OBJECTIVE: To study the prevalence, impact and dose–response relationship of comorbid chronic conditions on quality of life of type 2 diabetes patients. RESEARCH DESIGN AND METHODS: Cross-sectional data of 1676 type 2 diabetes patients, aged 31–96 years, and treated in primary care, were analyzed. Quality of life (QoL) was measured using the mental component summary (MCS) and the physical component summary (PCS) scores of the Short Form-12. Diagnosis of type 2 diabetes was obtained from medical records and comorbidities from self-reports. RESULTS: Only 361 (21.5 %) of the patients reported no comorbidities. Diabetes patients with comorbidities showed significantly lower mean difference in PCS [−8.5; 95 % confidence interval (CI) −9.8 to −7.3] and MCS scores (−1.9; 95 % CI −3.0 to −0.9), compared to diabetes patients without. Additional adjustments did not substantially change these associations. Both MCS and PCS scores decrease significantly with the number of comorbid conditions, yet most pronounced regarding physical QoL. Comorbidities that reduced physical QoL most significantly were retinopathy, heart diseases, atherosclerosis in abdomen or legs, lung diseases, incontinence, back, neck and shoulder disorder, osteoarthritis and chronic rheumatoid arthritis, using the backwards stepwise regression procedure. CONCLUSION: Comorbidities are highly prevalent among type 2 diabetes patients and have a negative impact on the patient’s QoL. A strong dose–response relationship between comorbidities and physical QoL was found. Reduced physical QoL is mainly determined by musculoskeletal and cardiovascular disorders.