Inpatient Costs for MS-Related Disease Relapse Higher for Males Than for Females

VBCN - May 2015 Volume 2, No 1

Washington, DC—The costs for inpatient care are significantly affected by the age and sex of patients with multiple sclerosis (MS) who experience disease relapse, according to data presented at the 2015 annual meeting of the American Academy of Neurology. The costs are greater for males than for females for all-cause hospitalizations, and these costs increase by age in both sexes.

“Among newly diagnosed patients with MS in a national database, inpatient rehabilitation stays had the highest cost compared with other diagnosis categories,” reported Chris M. Kozma, PhD, an independent research consultant and Adjunct Professor at the College of Pharmacy, University of South Carolina, Columbia. “And the cost of inpatient stays for all-cause and symptom-related diagnoses showed a significant age-by-sex effect.”

Relapses of MS can have a significant effect on patients’ quality of life and the management of costs related to treatment, according to Dr Kozma. Although recent literature has identified a disparity in MS incidence, relapse rates, and disease characteristics based on the sex of the patient, the influence of age and sex on the cost and duration of
inpatient encounters has not been well-studied.

“Essentially, using the IMS LifeLink dataset, we went in and identified those individuals who had an initial MS diagnosis,” said Amy Phillips of EMD Serono, who presented the findings, referring to the IMS LifeLink Health Plan Database. “We then looked at various ICD-9 [International Classification of Diseases, Ninth Revision] codes that might be indicative of a hospital-based relapse, stratifying by those different codes, whether it was an MS-specific code, other demyelinating disease, rehabilitation, or symptom-related visits. Finally, we examined the costs associated with those hospitalizations by that coding while looking at the effect of age and sex on those costs.”

A summation of costs per inpatient stay factored in the costs related to management services (provider costs related to the direct evaluation or management of a patient), surgical services, facility services, and ancillary services (cost of incidental services for the direct care of patients with MS). Researchers then evaluated the effects of age and sex on the average cost from the payer’s perspective and length of stay (LOS) per patient using a general linear model with robust variance estimation.

“We performed a cost model and a length-of-stay model, looking at the probability for effects on age and sex and age-by-sex interactions and identifying which of these had significant effects based on coding types within the hospitalization,” said Ms Phillips.

The study included 57,236 patients with MS, of whom 75% were female. The mean age was approximately 46 years.

Effects of Inpatient Care on Cost


The average cost of inpatient stay was greatest for patients receiving rehabilitation services; treatment of symptom-related conditions led to the lowest costs. The models for all-cause and symptom-related costs of inpatient care, controlling for age and sex, showed a significant age-by-sex interaction (P = .0007 and P = .0199, respectively), according to Dr Kozma.

“The age-by-sex interaction means that the cost of all-cause and symptom-related inpatient stays are different for males and females depending on how old they are,” noted Dr Kozma. “All-cause inpatient costs were higher for males than females, with costs increasing by age for both; however, cost for females increased at a greater rate with age.”

Because LOS accounts for a substantial portion of costs associated with MS relapse, researchers also sought to describe the impact of age and sex on LOS for all-cause and MS-related in­patient stays.

“For all-cause stays,” said Ms Phillips, “males had a greater LOS at all ages compared with females, showing a similar trend as the cost analysis….The cost of inpatient stays and LOS for MS-related diagnoses was significantly associated with an age effect.”

Although this study investigated the effects of age and sex on costs associated with relapsed disease, Ms Phillips acknowledged several variables not factored into the analysis that may affect costs related to patient hospitalizations (eg, comorbidities, disease severity, and current treatment). Despite these findings, questions still remain for researchers.

“Our analysis identifies the differences associated with age and sex on hospitalization costs,” concluded Ms Phillips, “but we’d like to know what may have caused or driven those differences.”

Related Items

Subscribe to Value-Based Care in Neurology

Stay up to date with the latest news in neurology by subscribing to receive the free VBCN e‑Newsletter.