Background and aims Systemic lupus erythematosus (SLE) predominantly affects individuals at peak age of productivity, and medical costs negatively impact on personal, family and community resources. This study aimed to identify annual medical costs and cost predictors among Filipino SLE patients.

Methods Direct annual healthcare costs were determined by survey questionnaires conducted among patients aged >18 years with minimum 1 year illness duration, consecutively seen at Lupus Clinics of University of Santo Tomas (UST) Hospital, Manila, Philippines from February to July 2016. Excluded were costs related to biologics. Predictors of cost were estimated using multiple regression analysis.

Results Respondents included 300 SLE patients (93.7% female) with mean age 32.84±9.89 (11-62) at diagnosis, mean disease duration 5.87±5.58 (1-36) years. Median and mean annual direct medical cost was Php 90 950 and Php 1 33 040 respectively (range Php 17 440–859,050). Annual cost was higher in those requiring dialysis (n=16) compared to nephritis without dialysis (n=150) vs without nephritis ever (n=134), (median Php 5 95 400 vs 1 44 700 vs 55 020), p<0.001. End stage renal disease (ESRD) (p<0.001), mycophenolate use (p<0.001), clinic visits (p=0.016) and hospitalisation (p=0.018) were independent variables which significantly contributed to annual costs. [Php47.5 = USD1]

Conclusions Nephritis especially if requiring dialysis was the most important cost predictor in this cohort, increasing annual costs up to 7 times. Mycophenolate use, frequency of hospitalisation and clinic visits increased annual costs by 147.2%, 173.8% and 2.6% respectively. This study reinforces need for early and aggressive disease control and prevention of complications especially in those with renal involvement.