Rheumatoid arthritis patients with comorbid depression and/or cardiovascular disease accumulated thousands more dollars in annual health care costs than did their peers with RA alone.
This finding is based on a study of over 10,000 people with rheumatoid arthritis conducted by Amie T. Joyce of Pharmetrics Inc., Watertown, Mass., and her associates.
“We are seeing increasingly that inflammation [is present in] many chronic diseases and, thus, it is impossible to separate out specific illness costs perfectly. The true costs are borne by people with comorbidity. When [other] studies exclude those with comorbidity, they exclude large fractions of the population,” said Edward H. Yelin, Ph.D.
Depression is also “rampant” in RA, “maybe two to three times higher than one would expect based on age and gender,” added Dr. Yelin, professor in residence of medicine and health policy in the division of rheumatology at the University of California, San Francisco. Dr. Yelin was not involved in the study.
Dr. Joyce's study looked at 10,298 RA patients culled from PharMetrics Inc.'s patient-centric database from Jan. 1, 2001 to Dec. 31, 2005. The database contains medical and pharmaceutical claims from 92 health plans across the United States. To be included in the study, patients had to be aged 18 years or older, have a diagnosis of RA, and have undergone treatment with a disease-modifying antirheumatic drug or biologic agent.
Of the sample, 8,916 patients had RA alone (86.6%), 608 had RA with CVD (5.9%), 716 had RA with depression (6.9%), and 58 patients had all three conditions (0.6%).
“Compared with patients with RA alone, patients with RA and depression, CVD, or CVD plus depression experienced significantly and progressively higher overall annual unadjusted healthcare costs,” wrote the authors. In fact, the annual cost for patients with RA alone was $14,257, vs. $21,410 for patients with RA plus depression, $24,444 for patients with RA plus CVD, and $35,246 for patients with all three conditions.
Interestingly, patients with RA plus depression had higher annual RA-specific costs than did patients with RA alone ($9,940 vs. $9,322; P = .014), and the RA-specific costs increased even more in patients with all three conditions, to $12,318 (P = .012). That effect was not seen in the RA plus CVD group (J. Rheumatol. 2009 Feb. 15 [doi:10.3899/jrheum.080670]).
The increased costs were, in part, the result of higher hospitalization rates. Just 7.9% of patients with RA alone had a hospital stay in the 12 months prior to their “index date” (the date of the patient's first claim with an RA diagnosis).
In the RA plus CVD cohort, this jumped to 34.9%. In the RA plus depression cohort, it was 18.6%, and among the patients who had all three diagnoses, 60.3% were hospitalized during that 12-month period. (For all rates, P was less than .001).
The average number of prescriptions filled also increased with increasing comorbidities. RA-only patients filled an average of 46.8 prescriptions in the 12 months following RA diagnosis, compared with 69.2 in the RA plus CVD group, 71.3 in the RA plus depression group, and 114.3 in the RA plus depression plus CVD group.
The authors disclosed that the study received funding from Wyeth Research. Three of the authors are also Wyeth Research employees.