Temporal trends in hospitalisation for opportunistic infections in lupus patients in Western Australia

Abstract

Background Lupus patients often require aggressive immunosuppressive therapy, which increases the risk for infections. We studied the temporal rates for opportunistic infections (OI) and associated mortality in lupus patients hospitalised in Western Australia. Methods All patients hospitalized in the period 1985–2015 with ≥2 ICD based diagnostic codes for SLE were included. OI was defined as a microbiologically confirmed mycobacterial, fungal, or viral infection. Descriptive data are given as median (IQR) and frequency (%) with incidence rates (IR) calculated per 1000 person years and IR trend rates analysed across 10-year periods by least square regression (R2). Results The study cohort (n = 1408) contained 85.3% females with age at entry 35 years (IQR 22–51). During median follow-up of 21.1 years (IQR 17.5–29.6) hospitalisation for OI occurred in 121 (8.6%) patients with recurrent or multiple OI observed in 42 (34.7%) patients. During 29.771 thousand person years, a total of 295 OI were diagnosed for an overall IR rate of 9.91 (CI 8.82–11.09)/1000 person years which did not decrease significantly over time (R2 0.14). Significant decreases were however seen in the IR for tuberculosis (R2 0.88), cryptococcal (R2 0.98) and pneumocystis (R2 0.98) infections, with increasing IR observed for other mycobacteria (R2 0.99) and aspergillosis (R2 0.55) and little change seen for H Zoster (R2 0.18) and Varicella (R2 0.10) infections. In-hospital death during OI admission occurred in 9/121 patients (7.4%). There was no significant gender difference in IR or outcome of OI. Conclusions Hospitalization rates for OI in lupus patients have not changed significantly over time, but there has been a clear shift in the underlying OI. The decrease in mycobacterial and pneumocystis infections suggest successful prophylaxis but the increase in viral and mycotic infections indicate a sustained need to improve prevention of these OI in lupus patients.