Background: Diabetes mellitus (DM) is a common metabolic disorder, which has negative outcomes on various medical conditions.

Objectives: This study aims to determine if DM has an impact on the outcomes of patients primarily admitted for rheumatoid arthritis (RA). The primary outcome is inpatient mortality, and secondary outcomes are hospital length of stay (LOS) and total hospital charge.

Methods: Data were extracted from the Nationwide Inpatient Sample (NIS) Database for 2016 and 2017. This database contains the largest collection of inpatient hospitalization data in the USA. NIS was searched for hospitalizations for RA as the principal diagnosis, with and without DM as a secondary diagnosis, using ICD-10 codes. Hospitalizations for adults from the above groups were included. Multivariate logistic and linear regression analysis was used to adjust for possible confounders for the primary and secondary outcomes respectively.

Results: Over 71 million hospitalizations were included in the combined 2016 and 2017 NIS database. There were 18,905 hospitalizations for those 18 years or older, who had RA as the principal diagnosis. Of these, 14,822 (78.4%) had no secondary diagnosis of DM and 4,083 (21.6%) had co-existing DM. RA hospitalizations had 175 inpatient deaths (0.93%), of which, 25 occurred in hospitalizations with DM (0.61%). The adjusted odds ratio (AOR) of inpatient mortality for RA with DM compared to without DM was 0.342 (95% CI: 0.137 - 0.85, P=0.021). In hospitalizations for RA with DM, there was a decreased mean adjusted LOS of 0.76 days (95% CI -1.26 - {-0.26}, P=0.003) compared to without DM. The adjusted mean total hospital charge for hospitalizations for RA with DM was lower by $6243 compared to without DM (95% CI -12250 - {-236}, P=0.042).

Conclusions: Hospitalizations for RA with co-existing DM had less inpatient mortality, LOS and total hospital charge compared to without DM. More studies are needed to determine if indeed DM is protective in hospitalizations for RA.


E. Edigin: None. S.T. Yap: None. H. Shaka: None. J. Xu: None. M. Padilla Sorto: None.

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