Co-morbidities in Finnish patients with rheumatoid arthritis: 15-year follow-up

Objectives: To study the prevalence and importance of co-morbidities in patients with rheumatoid arthritis (RA) at the time of the diagnosis and after a 15-year follow-up, focusing on the relationship between co-morbidity and disease activity. Method: The study population comprised 87 patients with early RA (mean age 44 years, 79% female, and 65% rheumatoid factor positive) collected from the Helsinki area between 1986 and 1989. Data for co-morbidities were collected at baseline and at a 15-year examination or at the time of death, and the age-weighted Charlson co-morbidity index (CCIa) at baseline was calculated for each patient. The disease activity score based on 28 joints (DAS28) was assessed with three parameters at baseline and during the first year (DAS28 AUC(0-12)). The relationship between comorbidity and activity of RA was studied in groups CCIa 0, CCIa 1-2, and CCIa >= 3. Results: Adequate data were available in 80 patients with a mean age of 60 years and a mean disease duration of 15.4 years. At baseline, 20% of patients had at least one co-morbid condition (CC). At endpoint, 60% of the patients had some co-morbidity: 34% had one CC, 19% two, 5% three, and 2% four CCs. The most common end-point CCs were hypertension (30%), cardiovascular diseases (14%), and malignancies (11%). DAS28 AUC(0-12) and DAS28 at endpoint were higher in groups CCI(a)1-2 and CCIa >= 3 than in CCIa 0. Conclusions: Co-morbidities increased during the 15 years of RA and the patients with high baseline CCIa showed higher disease activity both in early disease and at end-point.