Common comorbid and secondary conditions leading to hospitalization in multiple sclerosis patients in the United States.

OBJECTIVE

To identify the burden of hospitalization and common primary admitting diagnoses among MS patients in the United States (US).

BACKGROUND

The burden of hospitalizations and conditions leading to hospitalizations in MS patients in the US has not been well described.

DESIGN/

METHODS

Using the Nationwide Inpatient Sample for 2001-2010, all patients with principal or secondary diagnosis of MS were identified, and the principal admitting diagnoses were compared with that of non-MS patients. Trends in hospitalizations were studied in specific age groups (1-9 yrs, 10-19 yrs, 20-29 yrs, 30-39 yrs, 40-49 yrs, 50-59 yrs, 60-69 yrs,70-79 yrs, 80-84 yrs and ≥85 yrs), and population level rates were obtained and compared with non-MS patients to obtain rate ratios (RR) and odds ratios (OR).

RESULTS

A total of 1,240,410 MS patients were identified representing 4 out of every 1000 US hospital admissions, with an estimated female/male ratio of 2.72/1. The median age for MS hospitalizations was 53 years (Interquartile range=18). The majority of all MS hospitalizations occurred in the 30-69-year age bracket (82.17 %). The average length of in-patient hospital stays for MS patients compared to the non-MS population was 5.8 vs. 4.5 days (p < 0.001), and more MS patients had Medicare insurance (50.36 % vs. 42.24 %, p < 0.001). Overall, conditions such as urinary tract infections (UTI) - (RR11.43, p < 0.001), septicemia (RR8.53, p < 0.001), pneumonia (RR2.84, p < 0.001), chronic skin ulcers (RR20.64, p < 0.001), and lower limb and femoral neck fractures (RR2.86, p < 0.001) were present with increased frequency among MS patients. Patterns of comorbidity varied markedly by age group. The estimated average annual in-hospital charges adjusted to 2010 dollars for all MS inpatient hospitalizations was 3 billion U.S. dollars.

CONCLUSIONS

Patients with MS are admitted into hospital at a younger age, are hospitalized longer and consume more Medicare resources than the similar patients without MS in the general population. Infections account for a large proportion of MS-associated hospitalizations, from young adulthood onward. These findings are particularly significant in light of the increasing availability of disease modifying therapies with more potent immunosuppressive properties, as well as the accumulating data that systemic infection can drive MS relapses.