Very small retrospective study of rheumatic disease patients, sample size is too small for statistical significance (HCQ 0.5-4.0%, no-HCQ 0.4-2.7%). Confirmed cases were 1 HCQ and 2 no-HCQ, confirmed+likely cases were 1 HCQ and 3 no-HCQ. 1 HCQ and 2 no-HCQ patients were admitted to hospital. We do not think a conclusion can be drawn based on these sample sizes.
There are very significant differences between the groups, for example 30% of the HCQ group have SLE vs. 2.5% of the no-HCQ group. SLE patients have a 5.7 times relative risk of pneumonia according to , whereas the relative risk with glucocorticoids and TNF-α inhibitors is significantly lower . Two more recent studies with rheumatic disease/autoimmune condition patients provide higher confidence.
Macias et al., 5/16/2020, retrospective, database analysis, Spain, Europe, preprint, 12 authors.
risk of hospitalization, 25.5% lower, RR 0.74, p = 1.00, treatment 1 of 290 (0.3%), control 2 of 432 (0.5%).
risk of COVID-19 case, 49.0% higher, RR 1.49, p = 0.53, treatment 5 of 290 (1.7%), control 5 of 432 (1.2%).