GSTM1 and Hypokalemia: In logistic regression analysis adjusted for age, gender, day of fever, and one clinical factor at a time, we found that the leptospirosis group had more hypotension OR = 2.76 (95% CI 1.07–7.10), jaundice OR = 3.40 (95% CI 1.48–8.44), muscle pain OR = 2.12 (95% CI 1.06–4.26), acute kidney injury (AKI) OR = 2.90 (95% CI 1.31–6.15), low hemoglobin (Hb < 12 g/dL) OR = 3.48 (95% CI 1.72–7.04), and hypokalemia with hyponatremia (K < 3.5 mEq/L with Na < 135 mEq/L) OR = 3.56 (95% CI 1.17–10.84) than the non-leptospirosis group (Fig 2).