What Makes Treating Psoriatic Arthritis So Expensive?

New research on the cost of treating psoriatic arthritis indicates that, on average, the annual bill for medical care and prescription medication totals just under $20,000 per patient, but that total costs vary greatly among individual patients.

Investigators pulled MarketScan data from October 1, 2011 to September 30, 2012 for all adults who had enrolled for medical and pharmacy benefits for either psoriatic arthritis or ankylosing spondylitis at least 1 year before the beginning of the study period and continued to receive benefits for at least 1 year after the end of the study period.

The database provided information about costs associated with hospitalization, emergency care, office visits and pharmacy usage, as well as some baseline information about patient demographics and co-morbidities. Subsequent multivariate analysis looked for significant predictors of disease treatment costs both in baseline covariates and in patterns of treatment utilization.

Hypertension and hyperlipidemia were the most common comorbidities in patients with both conditions, and office visits (totaling about 11 trips per year) were the most common form of medical care, but there were also significant differences between the 2 cohorts.

Patients with ankylosing spondylitis were younger than patients with psoriatic arthritis and significantly more likely to be male. When it came to treatment, usage of both biologic and non-biologic disease-modifying drugs was more common among patients with psoriatic arthritis (61.1% and 52.4%, respectively) than it was among patients with ankylosing spondylitis (52.5% and 21.8%, respectively.)

Thanks largely to the greater tendency to use biologic drugs, prescription drugs costs for patients with psoriatic arthritis (mean, $14,174; standard deviation, $15,821) tended to be higher for than comparable costs for patients with ankylosing spondylitis (mean, $11,214; standard deviation, $14, 249). As a result, total mean cost of care was higher for patients with psoriatic arthritis despite their tendency to consume less direct medical treatment (mean, $5,108; standard deviation, $22,258 for patients with psoriatic arthritis vs. mean, $6,514; standard deviation, $32,982 for patients with ankylosing spondylitis).

“Multivariable regression analysis showed higher all-cause direct costs were associated with biologic use, age, and increased comorbidities in patients with ankylosing spondylitis or psoriatic arthritis (all p < 0.05),” the study authors wrote in The Journal of Rheumatology.

The new study’s finding that the direct medical costs of treating psoriatic arthritis now average almost $20,000 per patient per year in the US suggests that those costs more than tripled between 2000 and 2012. Indeed, a 2002 study published in The American Journal of Managed Care reported that the annual cost of medical care and medicine per US patient totaled just $3,638 in 2000. That study may have underestimated total costs, however, because it excluded patients who used biologics.

The increase in direct costs associated with psoriatic arthritis may be partially or fully countered by a decrease in indirect costs, such as unemployment, reduced productivity or patient suffering. For example, a 2011 study published in Rheumatology found that newer biologic treatments can be cost effective for some patients.

“The probability that etanercept is cost effective is 0.436 at a threshold of £20 000 per [quality-adjusted life year],” the authors of that analysis wrote. “Etanercept is also likely to be cost effective for patients with moderate to severe psoriasis or negligible skin involvement.”