Sex differences in electrolyte imbalances caused by SARS-CoV-2: a
case-control study
Abstract
Background - Since SARS-CoV-2 spread, evidences regarding sex
differences in progression and prognosis of COVID-19 have emerged.
Besides this, studies on patients’ clinical characteristics have
described electrolyte imbalances as one of the recurrent features of
COVID-19. Methods - We performed a case-control study on all patients
admitted to the emergency department (ED) from 1st March to 31st May
2020 who had undergone a blood gas analysis and a nasopharyngeal swab
test for SARS-CoV-2 by rtPCR. We defined positive patients as cases and
negatives as controls. The study was approved by the local ethics
committee Area 3 Milan. Data were automatically extracted from the
hospital laboratory SQL-based repository in anonymized form. We
considered as outcomes potassium (K+), sodium (Na+), chlorine (Cl-) and
calcium (Ca++) as continuous and as categorical variables, in their
relation with age, sex and SARS-CoV-2 infection status. Results - We
observed a higher prevalence of hypokalemia among patients positive for
SARS-CoV-2 (13.7% vs 6% of negative subjects). Positive patients had a
higher probability to be admitted to the ED with hypokalemia (OR 2.75,
95% CI 1.8-4.1 p<0.0001) and women were twice as likely to be
affected than men (OR 2.43, 95% CI 1.67-3.54 p<0.001). Odds
ratios for positive patients to manifest with an alteration in serum Na+
was (OR 1.6, 95% CI 1.17-2.35 p<0.001) and serum chlorine (OR
1.6, 95% CI 1.03-2.69 p<0.001). Notably, OR for positive
patients to be hypocalcemic was 7.2 (95% IC 4.8-10.6
p<0.0001) with a low probability for women to be hypocalcemic
(OR 0.63, 95% IC 0.4-0.8 p=0.005). Conclusions - SARS-CoV-2 infection
is associated with a higher prevalence of hypokalemia, hypocalcemia,
hypochloremia and sodium alterations. Hypokalemia is more frequent among
women and hypocalcemia among men.