Kwa MC, et al. Arthritis Care Res. 2017;doi:10.1002/acr.23190.

September 21, 2017
2 min read

Length of stay, cost of care greater for non-white patients with dermatomyositis


Kwa MC, et al. Arthritis Care Res. 2017;doi:10.1002/acr.23190.

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Nonwhite patients appear to have higher rates of admission, increased length of stay and higher cost of care associated with a diagnosis of dermatomyositis, according to findings.

In the study, researchers reviewed the 2002-2012 Nationwide Inpatient Sample (NIS), which is provided by the Agency for Healthcare Research and Quality’s Healthcare Cost and Utilization Project (HCUP). The NIS consists of roughly a 20% stratified representative cross-sectional sample of all hospitalizations in the U.S. for each year recorded. The researchers identified primary and/or secondary diagnoses of dermatomyositis using the appropriate ICD-9 CM code. A control group consisting of all hospitalizations without a diagnosis of dermatomyositis was also included.

The researchers determined the weighted prevalence (95% CIs) of hospitalization, either with primary or secondary dermatomyositis. They calculated the hospital cost of inpatient care based on the total charge of hospitalization and the cost-to-charge ratio determined by HCUP.

The researchers found that, overall, the NIS recorded 72,651,487 hospitalizations between 2002 and 2012. Of these, there were 2,042 admissions with a primary diagnosis of dermatomyositis (weighted frequency of 9,687) and 9,050 admissions with a secondary diagnosis of dermatomyositis (weighted frequency of 43,188). The weighted prevalence of primary dermatomyositis ranged from 29.8 million to 38.8 million patients per year, and the weighted prevalence of secondary dermatomyositis ranged from 115.8 million to 192.1 million patients per year. After 2003, there was a significant increase in the rates of hospitalization for patients with a primary or secondary diagnosis of dermatomyositis compared with the rates in 2002-2003.

Younger patient age was associated with hospitalization for primary dermatomyositis vs. hospitalization without a primary diagnosis of dermatomyositis (survey logistic regression, 40-59 years, OR = 0.77; 95% CI, 0.65-0.91; 60-79 years, OR = 0.45; 95% CI, 0.38-0.54; and older than 80 years, OR = 0.18; 95% CI, 0.14-0.23).

Multivariable logistic regression models with stepwise selection identified the following as associated with higher rates of dermatomyositis hospitalizations: female sex (adjusted OR = 2.05; 95% CI, 1.8-2.34), nonwhite race (African-American OR = 1.68; 95% CI, 1.57-1.79; Hispanic OR = 2.38; 95% CI, 2.22-2.55; Asian OR = 1.54; 95% CI, 1.32-1.81; and multiracial/other OR = 1.65; 95% CI, 1.48-1.88) and multiple chronic conditions (2-5: OR = 2.39; 95% CI, 2.2-2.6; and ≥ 6: OR = 2.8; 95% CI, 2.56-3.07).

A primary inpatient diagnosis of dermatomyositis was associated with a weighted total length of stay of 80,686 days, and an inflation-adjusted cost of care of $168,076,970, with geometric means of 5.38 (95% CI, 5.08-5.71) and $11,682 (95% CI, 11,013-12,392), respectively. Patients with dermatomyositis had significantly higher length of stay and costs of hospitalization vs. those without. Race/ethnicity was found to be linked to increased length of stay (log-linear regression: African-American adjusted beta level, 0.14; 95% CI, 0.04-0.25; Asian adjusted beta level, 0.51; 95% CI, 0.36-0.67).

“The findings of this study indicate that the inpatient burden of dermatomyositis is extensive,” the researchers wrote. “The cost and [length of stay] were consistently higher for patients with dermatomyositis than those without. Sex, nonwhite race and season were associated with higher rates of hospitalization, with African-American and Asian populations having an increased [length of stay, and Asian populations having an increased cost of care.” – by Jennifer Byrne


Disclosures: The authors report no relevant financial disclosures.