European Journal of Cardiovascular Medicine

Dengue virus infection frequently results in characteristic hematological and biochemical derangements, including thrombocytopenia, leukopenia, hemoconcentration, and elevations of liver enzymes. These changes are integral to dengue pathophysiology, reflecting plasma leakage, endothelial dysfunction, and host immune response.¹ In the clinical setting, serial laboratory monitoring is essential not only to confirm diagnosis but also to anticipate clinical worsening.²

Comorbid conditions such as diabetes mellitus may influence these laboratory trajectories. Diabetes is known to be associated with chronic low-grade inflammation, endothelial injury, and microvascular dysfunction, which could augment or alter the typical hematological and biochemical responses to dengue infection.³ Several observational studies have suggested that diabetic dengue patients may show more profound thrombocytopenia or delayed platelet recovery compared to non-diabetics. Chen CY et al.⁴ described significantly lower platelet counts in people with diabetes early during the infection course. Similarly, Singh R et al.⁵ found greater perturbations in inflammatory indices and hematological parameters in diabetic dengue patients.

Beyond hematological indices, biochemical markers (such as transaminases, renal function tests, and electrolyte changes) provide insight into organ involvement and disease severity in dengue. Elevated liver enzymes, for instance, often correlate with more severe disease and hepatic injury.⁶ The interrelation of hyperglycemia with viral replication and metabolic stress may further exacerbate hepatic, renal, or metabolic derangements in dengue. Indeed, recent mechanistic research indicates that hyperglycemia can facilitate dengue virus replication via metabolic pathways, increasing cellular stress and organ involvement.⁷

Given the biological plausibility and emerging clinical observations, the present study aims to systematically compare hematological and biochemical profiles between dengue patients with and without diabetes mellitus. Specifically, this work seeks to identify whether diabetes is associated with distinct laboratory abnormalities during dengue infection, which could help refine risk stratification and guide monitoring in this comorbid subgroup

Study Setting, Type, and Duration: The present study was undertaken in the Department of General Medicine at K. B. Bhabha Municipal General Hospital, Bandra (West), Mumbai. It was designed as a hospital-based cross-sectional analytical study aimed at evaluating hematological and biochemical alterations in dengue patients with and without diabetes mellitus. The data collection period extended from June 2023 to June 2024, covering a complete seasonal cycle of dengue transmission.

Study Participants: Patients aged 15–75 years who presented with acute febrile illness and were serologically confirmed as dengue positive (by NS1 antigen or IgM/IgG antibody ELISA) were recruited consecutively after obtaining informed consent. Both previously diagnosed diabetics and newly detected cases (HbA1c ≥ 6.5%) were included in the diabetic subgroup. Individuals with concurrent infections such as malaria, scrub typhus, enteric fever, leptospirosis, or COVID-19, as well as patients with sepsis, HIV/AIDS, chronic liver disease, or on hepatotoxic or nephrotoxic medications, were excluded. Pregnant and lactating women and those declining consent were also omitted.

Sample Size and Sampling Technique: The study included 100 confirmed dengue patients—25 with diabetes mellitus and 75 without diabetes—selected through purposive sampling during the study period. The sample size was calculated using a standard formula for estimating proportions at a 95% confidence level, assuming a prevalence of altered laboratory parameters in 50% of dengue patients and allowing a 10% margin of error. This ensured adequate power to detect clinically relevant differences between the groups.

Data Collection: Detailed demographic information and clinical examination findings were recorded using a structured case proforma. Venous blood samples were obtained at admission for complete blood count (CBC), hematocrit, platelet count, and differential leukocyte count. Biochemical investigations included liver function tests (serum bilirubin, alanine aminotransferase [ALT], aspartate aminotransferase [AST], alkaline phosphatase [ALP]), renal parameters (serum urea and creatinine), serum electrolytes (sodium and potassium), and random blood sugar. Glycated hemoglobin (HbA1c) was analyzed to classify diabetes status. Laboratory assays were performed in the hospital’s NABL-accredited central laboratory using automated analyzers with daily quality control checks.

Definitions and Classification: Thrombocytopenia was defined as a platelet count <150,000/µL and categorized as mild (100,000–149,000/µL), moderate (50,000–99,999/µL), or severe (<50,000/µL). Leukopenia was defined as a total leukocyte count <4,000/µL, and hematocrit ≥45% was considered elevated. Biochemical abnormalities were classified according to standard laboratory reference ranges. The severity of dengue infection was graded following the WHO 2009 criteria as dengue without warning signs, dengue with warning signs, and severe dengue.

Outcome Variables: The primary outcomes included comparison of hematological indices (hemoglobin, hematocrit, total leukocyte count, and platelet count) and biochemical parameters (liver and renal function tests) between diabetic and non-diabetic dengue patients. Secondary outcomes included the pattern and frequency of abnormal laboratory values and their association with clinical severity categories.

Ethical Considerations: The study protocol was reviewed and approved by the Institutional Ethics Committee of K. B. Bhabha Municipal General Hospital. Written informed consent was obtained from each participant before inclusion. All collected data were kept confidential and used solely for research purposes.

Data Analysis: Data were compiled and analyzed using Epi Info 7 software (CDC, Atlanta). Continuous variables were summarized as mean ± standard deviation, and categorical variables as frequencies and percentages. Group comparisons between diabetics and non-diabetics were performed using the independent-sample t-test for continuous variables and Chi-square or Fisher’s exact test for categorical data. A p-value < 0.05 was considered statistically significant.

Table 1 presents the comparison of key hematological indices between diabetic and non-diabetic dengue patients. The mean hemoglobin levels were comparable between both groups, indicating similar hydration and plasma leakage profiles at presentation. Total leukocyte counts were mainly within the normal range in both groups, though leukopenia (<4000/µL) was slightly more frequent among non-diabetics. Platelet counts showed a uniform decline across both cohorts, with people with diabetes demonstrating marginally lower mean values, though the difference was not statistically significant (p > 0.05). Hematocrit values did not differ meaningfully, suggesting that the degree of hemoconcentration was comparable between the two populations.

Table 1. Hematological Parameters in Dengue Patients

Categorical analysis of thrombocytopenia severity (Table 2) showed that moderate thrombocytopenia (50,000–99,999/µL) was the most frequent category in both groups. Severe thrombocytopenia (<50,000/µL) was marginally more common among diabetic patients (20%) compared to non-diabetics (14.7%), though this difference was not statistically significant (p = 0.49). This finding suggests that while diabetes may not independently influence the degree of platelet reduction, subtle trends toward more pronounced cytopenia could exist.

Table 2. Distribution of Thrombocytopenia Severity

Liver enzyme profiles are summarized in Table 3. Both groups exhibited elevated transaminase levels, a hallmark of dengue-associated hepatic injury. Mean AST and ALT levels were significantly higher among diabetic patients (AST: 145.3 ± 62.8 IU/L vs. 128.1 ± 55.2 IU/L; ALT: 135.9 ± 57.3 IU/L vs. 120.7 ± 49.1 IU/L, p < 0.05). Serum bilirubin values were mildly raised in both cohorts but did not differ significantly. The observation of greater hepatic enzyme elevation in people with diabetes may reflect compounded metabolic and inflammatory stress on the liver.

Table 3. Liver Function Parameters in Dengue Patients

*Significant at p < 0.05

Table 4 compares renal and electrolyte parameters. Mean serum urea and creatinine levels were mildly higher in diabetic patients, although both remained within near-normal limits. This difference did not reach statistical significance. Serum sodium levels were slightly lower among people with diabetes (133.8 ± 3.9 mmol/L vs. 135.2 ± 3.7 mmol/L, p = 0.06), indicating a tendency toward dilutional hyponatremia. Potassium levels were comparable across groups. These biochemical differences, though modest, suggest that people with diabetes may exhibit early biochemical perturbations reflective of renal or metabolic vulnerability.

Table 4. Renal and Electrolyte Parameters

In this study, the hematological alterations observed in dengue patients were broadly in line with the characteristic laboratory profile described in previous literature. Thrombocytopenia was a universal finding across both diabetic and non-diabetic groups, reflecting dengue-related marrow suppression and peripheral destruction. Although the mean platelet count was slightly lower among people with diabetes and the proportion of severe thrombocytopenia was numerically higher, the difference was not statistically significant. Comparable trends have been documented by Chen CY et al.,⁴ who reported a greater decline in platelet counts among diabetics but without consistent statistical separation from non-diabetics. Similar findings by Latt KZ et al.⁸ indicated that diabetes does not independently predict depth of cytopenia but may delay platelet recovery due to metabolic stress and endothelial dysfunction.

Leukopenia and marginal variations in hematocrit were also comparable between the two cohorts. This aligns with the observation by George T et al.,⁹ who found no meaningful difference in white cell suppression between diabetic and non-diabetic dengue groups, suggesting that diabetes does not significantly alter leukocytic response during the early viremic phase. These findings imply that while cytopenias remain a core laboratory feature of dengue, their severity may be more closely linked to viral pathophysiology than to underlying glycemic status.

The most notable group differences in this study were related to biochemical parameters, particularly hepatic enzymes. Diabetic patients demonstrated significantly higher AST and ALT levels, suggesting accentuated hepatic involvement. This has also been highlighted by Lee IK et al., who proposed that chronic inflammation and baseline oxidative stress in diabetics compromise hepatocellular reserve, rendering the liver more susceptible to dengue-related injury.¹⁰ Munish K similarly reported disproportionately higher transaminase elevations in diabetics, which they attributed to a convergence of metabolic derangement and viral cytopathic effect.¹¹

Renal and electrolyte changes in this study were mild but followed a consistent pattern, with diabetic patients exhibiting slightly higher serum urea and creatinine, and a greater tendency toward hyponatremia. Though not statistically significant, this observation is clinically relevant, as hyperglycemia-associated osmotic shifts and diabetic microangiopathy may contribute to renal vulnerability during systemic infection. Singh R et al.⁵ also described a higher frequency of biochemical perturbations in diabetics, even in the absence of overt organ failure, reinforcing the concept of reduced physiological reserve in this subgroup.

Taken together, the findings indicate that while the hematological profile of dengue remains broadly similar irrespective of diabetes status, biochemical abnormalities—particularly hepatic enzyme elevation and mild renal function derangement—tend to be more pronounced in diabetic patients. These trends suggest a potential interaction between chronic metabolic disease and dengue-related organ stress, underscoring the importance of closer biochemical surveillance in diabetic individuals during dengue infection.

The present study demonstrated that hematological abnormalities such as thrombocytopenia, leukopenia, and hematocrit changes occurred with comparable frequency in both diabetic and non-diabetic dengue patients. However, biochemical alterations, particularly hepatic enzyme elevation, were more pronounced among individuals with diabetes mellitus, along with a trend toward subtle renal and electrolyte disturbances. These findings suggest that diabetes does not markedly alter the hematological trajectory of dengue but may exacerbate hepatic and metabolic stress during infection. Routine biochemical monitoring, especially of liver function, may therefore be of greater clinical relevance in diabetic dengue patients to facilitate early detection of evolving organ dysfunction

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