ABSTRACT
BACKGROUND: COVID-19-induced diabetes is a novel and enigmatic disease. Our aim was to evaluate a possible relationship between post-COVID-19 syndrome (PCS) and increased insulin resistance (IR) in non-diabetic outpatients after mild COVID-19. METHODS: Repeated measures design. Three evaluations [1E (pre-COVID, baseline), 2E (3 months post-COVID) and 3E (21 months post-COVID)] were performed, directed to PCS+ and PCS- subjects. Triglyceride-glucose (TyG) index ≥8.74 was considered IR, and albumin-to-globulin ratio (AGR) <1.50, inflammation. RESULTS: We analyzed 112 individuals (median [IQR] age=44 [20] years, 58% women, 36 PCS+, 76 PCS-). PCS+ with very low basal IR (TyG <7.78, lowest quartile) showed a reduced inflammatory burden (basal AGR=1.81 [0.4] vs. 1.68 [0.2] in 2E; P=0.23), and increased TyG across evaluations (from basal 7.62 [0.2] to 8.29 [0.5]; P=0.018]. Conversely, PCS+ subjects with high basal TyG (TyG ≥8.65, highest quartile) did not show significant variations in TyG, but a greater inflammatory load (basal AGR=1.69 [0.3] vs. 1.44 [0.3] in 2E; P=0.10). In multivariable models addressing groups with reduced basal IR (TyG <8.01), PCS has been a consistent predictor for TyG, after adjusting for confounders. Partial correlation and multivariable analyses showed similarities involving acute polysymptomatic COVID-19 and PCS regarding IR. CONCLUSIONS: PCS was associated with increased IR, being more evident when the baseline degree of IR was very low. PCS and increased IR were separately associated with inflammation. Acute polysymptomatic COVID-19 and PCS could be clinical expressions of underlying inflammatory state, which in turn may also trigger IR.
ABSTRACT
BACKGROUND: ABO blood group system modulates the inflammatory response and has been implicated in COVID-19. Group O protects against SARS-CoV-2 infection, but there are no data regarding post-COVID-19 syndrome (PCS). Our aim was to assess this possible association. METHODS: Case-control study in a community setting, with subjects who had experienced mild COVID-19. Cases were PCS+, controls were PCS-, and the exposure variable, group O. We collected age, sex, BMI, smoking, comorbidities, inflammatory markers, anti-SARS-CoV-2 IgG antibodies, blood type and clinical data. Five composite inflammatory indices were developed. Multivariate analyses were performed. RESULTS: We analysed 121 subjects (56.2% women), mean age 45.7 ± 16 years. Blood group frequencies were 41.5%, 7.9%, 5.9%, and 44.5% for A, B, AB and O, respectively. Thirty-six patients were PCS+, without significant differences between cases and controls. Compared to non-O, a higher prevalence of PCS (p = .036), and number of symptoms of PCS (p = .017) were noted in group O. Concerning biomarkers, PCS + and PCS- showed no differences in A, B, and AB groups. In contrast, group O PCS + patients had significantly lower albumin-to-globulin ratio and higher lymphocyte count, fibrinogen, CRP levels, and higher percentages of 3 composite indices, than PCS- subjects. Group O showed a 6-fold increased risk of PCS, compared to non-O (adjusted OR = 6.25 [95%CI, 1.6-23]; p = .007). CONCLUSIONS: Group O has shown a consistent relationship with PCS, characterised by a more intense inflammatory burden than the other blood groups. Blood group O could be part of the immunological link between acute COVID-19 and PCS.
