Dengue fever, caused by the dengue virus of the Flaviviridae family and transmitted primarily by Aedes aegypti mosquitoes, is one of the most widespread arboviral infections worldwide. Its clinical spectrum ranges from a mild febrile illness to severe disease manifestations such as plasma leakage, hemorrhage, shock, and organ dysfunction. The global burden of dengue remains high, particularly in tropical and subtropical regions, where fluctuating epidemics stress health systems and complicate early diagnosis and management.1,2 As the epidemiology of dengue evolves, so does the profile of affected populations: adult patients and those with non-communicable diseases are increasingly being represented in dengue case series. In parallel, diabetes mellitus (especially type 2) is an escalating global health challenge, particularly in low- and middle-income countries.3,4 The coexistence of dengue and diabetes raises important clinical and public health questions about how underlying metabolic dysfunction may influence the presentation and severity of acute dengue infection.4,5 Biologically, diabetes is associated with chronic inflammation, endothelial dysfunction, impaired innate and adaptive immune responses, and microvascular changes. These pathophysiological alterations may modulate host response to dengue infection and could, in theory, lead to atypical clinical features or more subtle presentation in patients with diabetes.5,6 Several studies and meta-analyses have already indicated that diabetes is associated with increased risk of severe dengue and dengue-related mortality (e.g. Htun et al., meta-analysis OR ~1.75)7; more recent pooled evidence also suggests a stronger association between diabetes and severe manifestations (OR ~3.39)8. Still, most prior work has concentrated on outcomes (e.g. hemorrhagic complications, plasma leakage, shock) rather than on the initial clinical and demographic presentation in dengue. A limited number of comparative investigations have examined how dengue patients with diabetes differ in terms of baseline symptoms, vital signs, and anthropometric traits. For instance, a retrospective study in India compared clinical and laboratory features of dengue patients with and without diabetes, revealing similar predominant symptoms (fever, vomiting, body ache) but higher mortality in the diabetic subgroup9. Another work on dengue in diabetics noted worse appetite, renal derangements, and early functional decline as distinguishing features in diabetic dengue patients10. However, systematic prospective data focusing on demographic and initial clinical profile comparisons remain sparse. Understanding these differences is clinically valuable: if diabetics tend to present with variations in symptoms or vital parameters, clinicians could tailor triage, early monitoring, and intervention appropriately. It could also help refine risk stratification tools in dengue-endemic settings with rising noncommunicable disease burdens. Therefore, the present study was designed to prospectively compare the demographic characteristics, anthropometric measures, vital signs, and presenting symptoms of dengue patients with and without diabetes mellitus. The central aim is to identify any distinctive clinical patterns that may assist early detection, diagnosis, and management of dengue in the diabetic subgroup.

Study Setting, Type, and Duration This study was carried out in the Department of General Medicine at K. B. Bhabha Municipal General Hospital, Bandra (West), Mumbai. It was designed as an observational cross-sectional study and conducted over a period of one year, from June 2023 to June 2024. Study Participants The study population comprised patients aged 15–75 years with confirmed dengue infection, established by NS1 antigen or IgM/IgG antibody positivity on ELISA. Both male and female patients were included, and individuals with either a prior diagnosis of diabetes mellitus or newly detected diabetes, defined by HbA1c ≥ 6.5%, were eligible. Exclusion criteria encompassed patients outside the specified age range, those with alternative infections such as malaria, scrub typhus, enteric fever, or leptospirosis, individuals with sepsis or HIV/AIDS, patients on antiplatelet or anticoagulant therapy, pregnant or breastfeeding women, and those unwilling to provide informed consent. Sample Size and Sampling Technique The sample size was calculated using the formula for hypothesis testing of proportions: n=(Z^2 " " p(1-p))/L^2 Where, Z = 1.96 (at 95% confidence interval) p = assumed proportion of dengue among diabetics = 50% (for maximum sample size) L = margin of error = 10% Based on this calculation, the required sample size was 100. Among these, 25 patients were diabetics and 75 were non-diabetics. Sampling was done using a purposive sampling method, enrolling all eligible patients during the study period. Data Collection Data were obtained using a structured proforma following informed consent, and included demographic details such as age, sex, occupation, and residence; clinical parameters including duration of fever, presenting symptoms (headache, myalgia, arthralgia, retroorbital pain, rash, abdominal pain, vomiting, and bleeding tendency), along with vital signs like pulse, respiratory rate, systolic and diastolic blood pressure, and temperature; anthropometric measures comprising height, weight, and body mass index (BMI); diabetes status verified through patient history, medical records, or HbA1c ≥ 6.5%; and classification of dengue severity according to the WHO 2009 criteria into dengue without warning signs, dengue with warning signs, or severe dengue. Outcome Variables The outcome variables assessed in this study included differences in the clinical profile of dengue patients with and without diabetes, variations in vital signs at the time of presentation, and the distribution of symptoms along with anthropometric parameters across the two groups. Ethical Considerations The study was initiated after obtaining approval from the Institutional Ethics Committee. Written informed consent was obtained from all participants. Confidentiality and privacy of data were maintained. Participation was voluntary, and refusal to participate did not affect standard treatment. Data Analysis Data entry and analysis were performed using Epi Info CDC 7 software. Continuous variables were summarized as mean ± standard deviation, and categorical variables as proportions. Comparisons between diabetic and non-diabetic groups were performed using appropriate statistical tests, with a p-value <0.05 considered statistically significant.

As shown in Table 1, the mean age of diabetic dengue patients was slightly higher than that of non-diabetics, although the difference was not statistically significant. When age was categorized, the majority of diabetics clustered in the 41–60 years bracket, while non-diabetics were more evenly distributed across younger age groups, but again without significant variation. Gender analysis revealed a male predominance in both groups, with nearly identical proportions, suggesting no demographic skew related to sex. Table 1. Demographic Characteristics of Study Participants Variable Non-Diabetic (n=75) Diabetic (n=25) p-value Age (years) Mean ± SD 38.8 ± 15.4 42.8 ± 11.1 0.17 <20 10 (13.3%) 1 (4.0%) 21–40 25 (33.3%) 7 (28.0%) 0.27 41–60 37 (49.3%) 17 (68.0%) >60 3 (4.0%) 0 (0.0%) Gender Male 53 (70.7%) 18 (72.0%) 0.90 Female 22 (29.3%) 7 (28.0%) Table 2 highlights that fever and headache were universal presenting complaints in all patients. Myalgia and arthralgia were frequent but comparable across groups, while rash, retro-orbital pain, and gastrointestinal symptoms such as vomiting and loose stools did not differ appreciably. Notably, abdominal pain was reported by more than two-thirds of diabetics, almost double the proportion seen in non-diabetics, although this did not reach statistical significance. Bleeding manifestations were rare overall. Table 2. Clinical Features at Presentation Symptom/Sign Non-Diabetic (n=75) Diabetic (n=25) p-value Fever 75 (100.0%) 25 (100.0%) NA Headache 75 (100.0%) 25 (100.0%) NA Myalgia 55 (73.3%) 15 (60.0%) 0.22 Arthralgia 20 (26.7%) 5 (20.0%) 0.60 Retro-orbital pain 20 (26.7%) 7 (28.0%) 1.00 Rash/Pruritus 31 (41.3%) 10 (40.0%) 0.21 Abdominal pain 23 (30.7%) 17 (68.0%) 0.81 Vomiting 26 (34.7%) 10 (40.0%) 0.64 Loose motion 6 (8.0%) 3 (12.0%) 0.69 Bleeding tendency 1 (1.3%) 0 (0.0%) 1.00 Vital sign assessment (Table 3) showed no meaningful differences in pulse rate, respiratory rate, or body temperature between the two groups. However, systolic blood pressure was modestly but significantly lower among diabetic patients compared to non-diabetics. Diastolic blood pressure was similar in both cohorts. These findings indicate that, while most vital signs were stable, subtle variations in hemodynamic parameters may be observed in diabetic individuals at presentation. Table 3. Vital Parameters Parameter Non-Diabetic (n=75) Diabetic (n=25) p-value Pulse (beats/min) 80 ± 12 79 ± 11 0.95 Respiratory rate (/min) 20 ± 5 19 ± 6 0.21 Systolic BP (mmHg) 125 ± 15 120 ± 14 0.037* Diastolic BP (mmHg) 80 ± 10 78 ± 11 0.60 Temperature (°F) 98.6 ± 1.2 98.7 ± 1.3 0.47 *Significant at p < 0.05 Table 4. Blood Sugar and HbA1c Profile Parameter Non-Diabetic (n=75) Diabetic (n=25) p-value Fasting Blood Sugar (mg/dL) 85.2 ± 9.5 100.1 ± 10.0 <0.05 Postprandial Blood Sugar (mg/dL) 115.4 ± 18.2 140.2 ± 20.0 <0.05 HbA1c (%) 5.47 ± 0.44 6.85 ± 0.42 <0.05 HbA1c category <5.7% 60 (80.0%) 1 (4.0%) <0.005 5.7–6.4% 15 (20.0%) 10 (40.0%) ≥6.5% 0 (0.0%) 14 (56.0%) Table 4 demonstrates clear metabolic distinctions between the groups. Diabetic patients exhibited significantly higher fasting and postprandial blood glucose levels, along with elevated HbA1c compared to non-diabetics. Stratification of HbA1c values revealed that more than half of diabetics had poor glycemic control (≥6.5%), while the vast majority of non-diabetics fell in the normal range (<5.7%). These data reinforce the metabolic differentiation between the two cohorts and validate the classification of participants into diabetic and non-diabetic categories.

In the present study, the demographic profile of dengue patients revealed that diabetics had a slightly higher mean age than non-diabetics, although the difference was not significant. Most diabetics were clustered in the 41–60 years group, whereas non-diabetics were distributed more evenly across younger age brackets. Similar findings were reported by Singh R et al.,11 who noted a predominance of middle-aged adults in both diabetic and non-diabetic dengue patients, with no significant age-related variation. Likewise, Munish K et al.12 observed that while mean ages differed slightly between the two groups, age was not an independent determinant of clinical severity. This suggests that although diabetes is more common in older individuals, age itself may not distinctly modify the initial clinical profile of dengue. Male predominance was observed in both groups in the present study, which is consistent with several earlier reports. George T et al.9 documented that males formed nearly two-thirds of their dengue cohort irrespective of diabetes status, while Latt KZ et al.13 also confirmed male predominance without significant gender differences between diabetic and non-diabetic patients. These findings indicate that sex distribution is unlikely to confound comparative assessments of clinical presentation in this context. With respect to clinical features, fever and headache were universal in both groups, while myalgia, arthralgia, retro-orbital pain, and rash were common but did not differ significantly. These findings align with observations by Chen CY et al.,14 who demonstrated that classical dengue symptoms occur at comparable frequencies in diabetic and non-diabetic patients. However, a noteworthy finding in the current study was the higher prevalence of abdominal pain among diabetics. Lee et al.15 similarly reported that diabetics more often presented with abdominal discomfort and gastrointestinal complaints, which were associated with worse outcomes in some cases. This suggests that abdominal pain may serve as an early clinical marker of greater physiological stress in diabetic patients with dengue, even when severity criteria are not yet met. Vital sign analysis showed that most parameters, including pulse rate, respiratory rate, diastolic blood pressure, and temperature, were comparable across the two groups. However, systolic blood pressure was significantly lower in diabetics. Latt KZ et al.13 also reported subtle hemodynamic differences, though their findings suggested higher systolic pressures in diabetic subgroups, potentially influenced by background antihypertensive use. The modest but significant reduction in systolic pressure in our diabetic patients could reflect early endothelial dysfunction and impaired vascular tone, consistent with the known pathophysiological impact of chronic diabetes on vascular health. Blood sugar and glycemic control data reaffirmed the metabolic distinction between the groups. Diabetics demonstrated significantly higher fasting and postprandial glucose levels, with more than half having poorly controlled diabetes (HbA1c ≥6.5%). Singh R et al.11 emphasized that poor glycemic control worsens inflammatory responses in dengue and predisposes patients to severe outcomes. Similarly, Munish K et al.12 found that diabetic patients with uncontrolled blood sugars had a higher risk of complications and prolonged recovery. These findings underline the importance of evaluating glycemic status at presentation, as it may influence not only outcomes but also symptomatology, such as the heightened abdominal pain noted in this study. Taken together, the current study demonstrates that while most clinical features and demographic characteristics of dengue patients were similar irrespective of diabetes, subtle but important differences were evident. Abdominal pain was more frequent, systolic blood pressure was marginally lower, and glycemic control was markedly worse in diabetic patients, all of which could have clinical implications for early risk stratification. The consistency of these findings with prior literature reinforces the need for heightened vigilance in diabetic patients presenting with dengue, even in the absence of overt severity markers.

The comparative analysis revealed that while the overall demographic and clinical presentation of dengue was largely similar between diabetic and non-diabetic patients, certain distinctions were noteworthy. Diabetic individuals more frequently experienced abdominal pain and exhibited significantly lower systolic blood pressure, along with consistently poorer glycemic control. These findings suggest that underlying diabetes may subtly modify the clinical expression of dengue, potentially reflecting altered vascular and metabolic responses. Recognition of these differences is important for clinicians, as early identification and vigilant monitoring of diabetic patients with dengue could aid in timely risk stratification and improved patient management.

1. Kularatne SA, Dalugama C. Dengue infection: Global importance, immunopathology and management. Clin Med (Lond). 2022 Jan;22(1):9-13. 2. Pourzangiabadi M, Najafi H, Fallah A, Goudarzi A, Pouladi I. Dengue virus: Etiology, epidemiology, pathobiology, and developments in diagnosis and control–A comprehensive review. Infection, Genetics and Evolution. 2024 Dec 26:105710. 3. Murray NE, Quam MB, Wilder-Smith A. Epidemiology of dengue: past, present and future prospects. Clin Epidemiol. 2013 Aug 20;5:299-309. 4. Dos Santos BF, Gandolfi FA, Milhim BHGA, Dourado FS, Silva GCD, Zini N, Gratão VHR, Mariani MP, Abbas TN, Garcia PHC, Rocha RS, Vasilakis N, Nogueira ML, Estofolete CF. Diabetes as risk factor to severity of dengue in naïve patients. medRxiv [Preprint]. 2024 Apr 29:2024.04.27.24306485. 5. Shawon SR, Hamid MKI, Ahmed H, Khan SA, Dewan SMR. Dengue fever in hyperglycemic patients: an emerging public health concern demanding eyes on the effective management strategies. Health Sci Rep. 2024 Oct 16;7(10):e70144. 6. Sekaran SD, Liew ZM, Yam HC, Raju CS. The association between diabetes and obesity with Dengue infections. Diabetol Metab Syndr. 2022 Jul 21;14(1):101. 7. Htun NS, Odermatt P, Eze IC, Boillat-Blanco N, D'Acremont V, Probst-Hensch N. Is diabetes a risk factor for a severe clinical presentation of dengue?--review and meta-analysis. PLoS Negl Trop Dis. 2015 Apr 24;9(4):e0003741. 8. Lu HZ, Xie YZ, Gao C, Wang Y, Liu TT, Wu XZ, Dai F, Wang DQ, Deng SQ. Diabetes mellitus as a risk factor for severe dengue fever and West Nile fever: A meta-analysis. PLoS Negl Trop Dis. 2024 May 31;18(5):e0012217. 9. George T, Pais ML, D’silva P, Natarajan S, Jakribettu RP, Baliga MS. Comparative study of Clinicolaboratory parameters of dengue in diabetic and non-diabetic from a tertiary care hospital. IP Int J Med Microbiol Trop Dis. 2022;8(3):260-6. 10. Issop A, Bertolotti A, Diarra YM, Maïza JC, Jarlet É, Cogne M, Doussiet É, Magny É, Maillard O, Belot J, Cadic M. Dengue clinical features and harbingers of severity in the diabetic patient: A retrospective cohort study on Reunion island, 2019. Travel medicine and infectious disease. 2023 Jul 1;54:102586. 11. Singh R, Goyal S, Aggarwal N, Mehta S, Kumari P, Singh V, et al. Study on dengue severity in diabetic and non-diabetic population of tertiary care hospital by assessing inflammatory indicators. Ann Med Surg. 2022;82. 12. Munish K, Singhal G, Gupta A. Correlation between diabetics and non-diabetics recovery in hospitalized dengue positive patients. Int J Life Sci Biotechnol Pharm Res. 2024;13(7):260. 13. Latt KZ, Poovorawan K, Sriboonvorakul N, Pan-ngum W, Townamchai N, Muangnoicharoen S. Diabetes mellitus as a prognostic factor for dengue severity: retrospective study from Hospital for Tropical Diseases, Bangkok. Clin Infect Pract. 2020;7:100028. 14. Chen CY, Lee MY, Lin KD, Hsu WH, Lee YJ, Hsiao PJ, et al. Diabetes mellitus increases severity of thrombocytopenia in dengue-infected patients. Int J Mol Sci. 2015;16(2):3820-30. 15. Lee K, Hsieh CJ, Lee CT, Liu JW. Diabetic patients suffering dengue are at risk for development of dengue shock syndrome/severe dengue: emphasizing the impacts of co-existing comorbidity(ies) and glycemic control on dengue severity. J Microbiol Immunol Infect. 2020;53(1):69-78.