Title : Redefining scrub typhus severity: Evidence from a tertiary care hospital of North India
Abstract:
Background: Scrub typhus is a leading cause of acute undifferentiated febrile illness across India, with a rising burden of multiorgan dysfunction and mortality. Current severity classification systems are inconsistent across studies and do not adequately integrate radiological and biochemical predictors. This study aimed to redefine scrub typhus severity using clinical, laboratory and chest radiographic parameters from a large cohort in North India.
Methods: A retrospective observational study was conducted at a tertiary care hospital in North India including 220 IgM-confirmed scrub typhus patients. Demographic, clinical, laboratory and radiological data were extracted. Chest X-ray PA view severity was graded numerically (0–4). Statistical analysis included chi-square/Fisher’s test, independent t-test, univariate and multivariable logistic regression, odds ratios (OR) with 95% CI, Pearson correlations and ROC curve analysis. Outcomes were categorized as Live = 0 and Dead = 1.
Results: Out of 220 patients, 20 (9.1%) died. Non-survivors exhibited significantly elevated levels of SGOT, SGPT, CRP, urea, creatinine, amylase, and lipase, together with hyponatremia, hypokalemia and hypocalcemia. Platelet counts were significantly reduced in severe cases. Multivariable analysis identified SGOT, SGPT, creatinine, and CRP as independent predictors of mortality. The multivariable ROC curve demonstrated excellent discrimination (AUC ≈ 0.91). Chest X-ray severity correlated strongly with hepatic, renal and pancreatic dysfunction—SGOT (r ≈ 0.52), SGPT (r ≈ 0.49), urea (r ≈ 0.44), creatinine (r ≈ 0.41), amylase (r ≈ 0.39), lipase (r ≈ 0.36) with p < 0.001. Higher CXR grades (≥3) were significantly associated with MODS, pneumonia, shock and mortality.
Conclusion: Scrub typhus severity is closely linked to hepatic, renal and pancreatic dysfunction, with chest X-ray severity emerging as a strong surrogate marker for systemic involvement. The findings support a revised, evidence-based severity classification that incorporates radiographic grade, hepatic–renal biomarkers and inflammatory markers, demonstrating substantially improved predictive performance over traditional criteria.
Keywords: Mortality predictors, Multiorgan dysfunction, Scrub typhus, Severity predictors.
