LISBON – Psoriasis and diabetes are expensive diseases, and patients with both conditions experience a synergistic increase in health care utilization and costs that is significantly greater than the incremental economic burden imposed by each disease individually.
In other words, patients with comorbid psoriasis and diabetes have more hospitalizations and outpatient visits over the course of a year than would be expected simply from adding together the increased use typical of patients with psoriasis to that of patients with diabetes, compared with health care use by individuals with neither condition, Dr. Frank Zhang reported at the annual congress of the European Academy of Dermatology and Venereology.
This is an observation with important implications for health economics. These are two common diseases. Psoriasis affects 2%-3% of the world's population, with 260,000 new cases arising per year in the United States alone. Psoriasis predisposes to insulin resistance, and psoriasis patients have a one-third greater risk of diabetes than the general population, noted Dr. Zhang of Celgene Corporation, Summit, N.J.
Because the economic impact of having both diseases had not been addressed, he and his colleagues conducted a retrospective study of 106,128 patient pairs matched for age and gender, one member of each pair having psoriasis and the other free of the disease. The patients were drawn from the Thomson Reuters MarketScan Research Databases for 2004 through June 2009.
Sixteen percent of the psoriasis patients had diabetes, significantly greater than the 13% with diabetes in the control group.
Psoriasis patients with diabetes averaged 17 more hospitalizations per 100 patient-years and 5.8 more outpatient visits per year than did psoriasis patients without diabetes. Furthermore, patients with diabetes and psoriasis averaged five more hospitalizations per 100 patient-years and 6.3 additional outpatient visits per year, compared with nonpsoriatic patients with diabetes.
The most likely explanation for this synergistic health care burden in the dual-diagnosis patient lies in the complexity entailed in managing the two diseases simultaneously, said Dr. Zhang.
Total annual health care costs in patients with both psoriasis and diabetes averaged $19,536, compared with $13,589 for psoriasis-free patients with diabetes and $5,539 in those who had psoriasis but not diabetes.
The study was funded by Celgene, where Dr. Zhang is employed.