Diabetes Can Make Dengue More Lethal!

Introduction

More than 80 million people in India live with diabetes, and statistics say that more than 2 lakh people contract dengue every year^1,2. Are you wondering why we are linking the two illnesses? Read on to know why.

It turns out that diabetes can worsen the complications caused by dengue, and now that winter is almost here, the dengue menace has shot up, too. If you are a diabetic, you should be extra cautious about mosquitoes this season, because dengue is more dangerous for you than for non-diabetics. 

Diabetes and Dengue: The Deadly Combination

Dengue infection in patients with pre-existing diabetes is associated with significantly higher morbidity and mortality compared to non-diabetic individuals.

Evidence from Chennai shows that among dengue patients, approximately 30% had diabetes, and these patients were more likely to experience severe complications. Diabetic dengue patients frequently present with classical symptoms such as fever, vomiting, headache, muscle and body pain, but they are also prone to severe manifestations, including reduced urine output, bleeding tendencies, pedal oedema or ascites (swelling in feet or stomach), pleural effusion (fluid in lungs), and altered sensory stimulation. Blood abnormalities such as anaemia, thrombocytopenia, and leucocytosis (reduced red blood cells and platelets and increased white blood cells, respectively) are more pronounced in diabetic patients, contributing to worse outcomes³.

A prospective study further demonstrated that dengue-infected individuals with diabetes exhibit elevated inflammatory markers (CRP, Endocan, IL-8, and perfusion index). This indicated a heightened inflammatory response that can further increase blood sugar levels and the risk of severe dengue and bleeding disorders⁴.

It has been shown that in some diabetes patients, dengue caused very severe complications. They may suffer from respiratory problems, persistent vomiting, sore throat that makes swallowing difficult and continuous coughing. Also, intense abdominal pain, extremely high fever and splitting headaches may be higher in diabetics with increased chances of developing Dengue Haemorrhagic Fever (DHF). DHF is a more serious form of dengue, with bleeding tendencies, a low platelet count, and possible damage to the circulatory system^5,6.

Blood glucose is an important factor for viral replication, and it basically facilitates virus transmission in mosquitoes, dengue causes fever and increases metabolic rate, which can lead to a rise in fluctuation in blood sugar levels, strict monitoring is very critical.

Dr Ashish Bajaj, M.B.B.S., M.D. in Clinical Pharmacology and Toxicology

Why Diabetics Have a Higher Risk of Severe Dengue?

A common question is why diabetes appears to make dengue more dangerous. While the complete picture is still being studied, researchers point to several overlapping mechanisms that explain the dengue and diabetes risk seen in clinical practice⁶.

• Chronic inflammation: Diabetes is a state of ongoing, low-grade inflammation. Dengue can also trigger a strong inflammatory response, with high levels of markers such as CRP, Endocan, and IL-8. When dengue is added on top of the existing inflammation of diabetes, the combined inflammatory load may be greater, which is associated with more severe disease.
• Weakened immunity: Poorly controlled blood sugar can impair how immune cells respond to infection. This may make it harder for the body to clear the dengue virus efficiently and may slow recovery.
• Endothelial dysfunction: The endothelium is the thin inner lining of blood vessels. In diabetes, this lining is often damaged and may not be able to regulate fluid balance. Dengue also attacks the endothelium, so the two conditions together may compound blood vessel injury.
• Increased capillary leak risk: In severe dengue, the walls of the smallest blood vessels (capillaries) become “leaky.” Imagine a garden hose that develops tiny pinholes, fluid that should stay inside the vessel seeps out into the surrounding tissues. This capillary leak (plasma leakage) is why severe dengue can cause accumulation of fluid around the lungs and abdomen, while the blood left in the vessels becomes concentrated, and blood pressure can fall. Because diabetes already weakens the blood vessel lining, diabetics may be more vulnerable to this leakage

HbA1c and Dengue

HbA1c is a blood test that reflects your average blood sugar over the past 2–3 months, rather than a single reading. It is a useful marker of how well diabetes has been controlled over the longer term⁶.

Why does this matter during dengue? Poor long-term glucose control (a higher HbA1c) is associated with more pronounced chronic inflammation, greater changes in blood vessel function (endothelial dysfunction), and altered immune responses. Studies suggest that people whose diabetes is poorly controlled may face a higher risk of complications when they develop an acute infection like dengue. However, HbA1c alone cannot predict how severe dengue will become in an individual patient. 

In simple terms, a well-controlled HbA1c does not make you immune to dengue, but good baseline sugar control may put your body in a stronger position to cope with the stress of infection.

Blood Sugar Monitoring During Dengue

Fever and infection trigger the release of stress hormones, which can push blood sugar up, while reduced appetite, vomiting, or skipped meals can pull it down. The result is that glucose levels can swing unpredictably, which is why blood sugar monitoring during dengue needs to step up.

General guidance on how often to check (always follow your own doctor’s advice, as individual needs may differ)¹⁰:

• Mild cases, managed at home, eating and drinking normally: Many patients are advised to check blood glucose more frequently than usual, often several times a day, such as before meals and at bedtime, to catch changes early.
• More symptomatic cases (poor appetite, vomiting, high fever): Checks may need to be more frequent, as the risk of both high and low sugar rises when food intake is irregular. Report unstable readings to your doctor promptly.
• Hospitalized patients: Glucose is typically monitored closely by the medical team, sometimes every few hours, especially when intravenous fluids or insulin are used.

The key message is that infection makes sugar control less predictable, so monitoring should increase during dengue rather than stay the same.

Insulin Adjustment During Dengue

During dengue, your usual diabetes regimen may need to change. Reduced food intake, vomiting, and fever can all alter how much insulin or medication your body needs. In some cases, insulin doses may need to be increased; in others, reduced to avoid dangerously low sugar¹¹.

This is critically important: any change to insulin doses or diabetes medication during dengue must be made only by your doctor. Please do not self-adjust your insulin or stop your medication on your own based on home readings. The balance between high and low blood sugar during dengue is delicate, and getting it wrong in either direction can be harmful. Share your glucose readings and symptoms with your doctor and let them guide any adjustments.

When Diabetics with Dengue Should Be Hospitalized Earlier

People with diabetes may need extra care in the hospital than non-diabetics, because warning signs can escalate faster. Seek medical attention urgently and do not wait if you or a loved one with diabetes and dengue experience any of the following:

• Persistent vomiting that prevents keeping food or fluids down
• Signs of dehydration, such as very little urine, dry mouth, or extreme thirst
• High or unstable blood sugar that is difficult to control, or repeated low-sugar episodes
• Falling platelet counts accompanied by bleeding, bruising, or warning symptoms
• Dizziness, fainting, or low blood pressure
• Inability to eat or drink adequately
• Worsening weakness, drowsiness, or confusion
• Difficulty breathing or severe abdominal pain 

These can be early signals of plasma leakage or progression toward severe dengue, and prompt hospital care can be lifesaving.

Comorbidity Statistics

Real-world data underline why this matters, especially in India and South Asia¹²:

• In the Chennai-based hospital study⁶, approximately 30% of dengue patients had diabetes, and these patients more often had severe laboratory abnormalities and complications.
• A prospective Indian study⁴ found that diabetic dengue patients showed higher inflammatory markers (CRP, Endocan, IL-8) and were at greater risk of severe dengue and bleeding disorders.
• Public health reviews describe dengue–diabetes comorbidity as an emerging public health threat, noting that diabetes is associated with an increased risk of severe dengue outcomes.

Given India’s very high diabetes burden and recurring dengue outbreaks, this overlap affects a large number of people every season.

Dengue Shock Syndrome

In cases of dengue in non-diabetics, patients may experience no symptoms, mild symptoms, or severe symptoms. These classical dengue symptoms may include headaches, rashes, low white blood cell levels, nausea, weakness and of course fever. As mentioned above, sometimes dengue may be very severe, increasing blood vessel wall permeability (bleeding tendency), causing the condition Dengue Haemorrhagic Fever (DHF). This condition is more common and likely to progress in diabetics⁶.

As this condition progresses, it may go on to something called Dengue Shock Syndrome. This is characterised by the same symptoms of internal haemorrhage, low pulse, change in mental state, and change in blood pressure that happen with DHF. Additionally, dengue shock syndrome results in multiple organ failures, failure in the circulatory system and a high risk of death⁷.

Overall, these findings show that diabetes significantly amplifies the severity and complications of dengue, underscoring the critical need for vigilant monitoring, prompt intervention, and individualised care in diabetic patients during dengue outbreaks.

Pathologically, dengue is characterised by high levels of inflammatory markers like CRP, endocan and IL-8. Thus, the dengue could be more fatal in patients that have co-morbid conditions of inflammation such as in diabetes.

Dr. M.G. Kartheeka, MBBS, MD(Pediatrics)

Why Does Diabetes Magnify Dengue Complications?

There is not enough evidence that tell us why diabetes makes dengue more dangerous. But doctors believe that since a person with diabetes has weak immunity, fragile blood vessels, and a higher risk of haemorrhage, symptoms of dengue tend to worsen in diabetics⁷. Dengue destroys a person’s platelets, which may lead to blood clotting. Together, diabetes and dengue cause a lot of damage inside the body and make it difficult for the diabetic to recover⁶.

What Can You Do?

Winter, especially the beginning of winter, is when dengue incidents peak. Here are a few things that diabetics can do⁹:

• Always use mosquito nets when you sleep at night.
• When you go out, apply mosquito-repellent cream on your arms, legs, and neck.
• Use mosquito-repellent oils at all times of the day when you are home.
• Do not let water accumulate near your home, or mosquitoes will breed there.
• Wear outfits and shirts with long sleeves.
• As for your diabetes, monitor your blood sugar level regularly.
• Do not forget your insulin shots and medication.
• Stick to the prescribed diet and exercise routine.

Also Read: 5 Effective Preventive Measures for Dengue

If you have diabetes, you have to be extra careful about mosquitoes. Follow the precautions mentioned above to stay healthy and safe.

When to Consider Testing?

If you have diabetes and develop fever, body ache, headache, or other dengue-like symptoms during the season, timely testing helps guide care before complications set in.

• Consider a dengue test if you have a fever with warning signs, especially during an outbreak period.
• Check your blood glucose levels, since infection can destabilise sugar control even if your diabetes is usually well managed.
• If you are symptomatic, a combined dengue and diabetes screening can give your doctor a fuller picture in one go.

Speak with a qualified doctor about which tests are right for you. Early information supports safer, faster decisions.

Conclusion

Diabetes greatly increases the risk of severe complications and poor outcomes in dengue. This makes early detection, close monitoring, and timely management especially vital for diabetics who get dengue symptoms. Although prompt identification and medical therapy are cornerstone of management, the importance of prevention cannot be overlooked especially during periods of outbreaks.

Also Read: Dengue: The Silent Threat of the Monsoon Season

References

1. International Diabetes Federation. India Diabetes Statistics & Health Data. [Internet]. IDF Diabetes Atlas; [cited 2025 Sep 26]. Available from: https://diabetesatlas.org/data-by-location/country/india/
2. Press Information Bureau, Government of India [Internet]. Ministry of Health and Family Welfare; [cited 2025 Sep 26]. Available from: https://www.pib.gov.in/PressReleasePage.aspx?PRID=2040968
3. 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 [Internet]. IP Int J Med Microbiol Trop Dis. 2022 [cited 2025 Sep 26];8(3):260-6. Available from: https://doi.org/10.18231/j.ijmmtd.2022.051
4. Singh R, Goyal S, Aggarwal N, Mehta S, Kumari P, Singh V, Chopra H, Emran TB. Study on dengue severity in diabetic and non-diabetic population of tertiary care hospital by assessing inflammatory indicators. Ann Med Surg (Lond). 2022 Sep 16;82:104710. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC9577853/
5. Bisanzio D, Estofolete CF, Reithinger R. Dengue and diabetes comorbidity: an emerging public health threat. International Health.2025; 17 (4): 597–599. Available from: https://academic.oup.com/inthealth/article/17/4/597/7925169
6. 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. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC11483528/
7. Rajapakse S. Dengue shock. J Emerg Trauma Shock. 2011 Jan;4(1):120-7. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC3097561/
8. Sekaran SD, Liew ZM, Yam HC, et al. The association between diabetes and obesity with dengue infections. Diabetol Metab Syndr. 2022;14:101. Available from: https://dmsjournal.biomedcentral.com/articles/10.1186/s13098-022-00870-5
9. Centers for Disease Control and Prevention. Dengue Case Management Pocket Guide [Internet]. CDC; [cited 2025 Sep 26]. Available from: https://www.cdc.gov/dengue/media/pdfs/2024/05/20240521_342849-B_PRESS_READY_PocketGuideDCMC_UPDATE.pdf
10. Weng SC, Tsao PN, Shiao SH. Blood glucose promotes dengue virus infection in the mosquito Aedes aegypti. Parasit Vectors. 2021;14:376. doi:10.1186/s13071-021-04877-1. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC8314564/
11. Liu X, Liang Z, Duan H, Yu J, Qin Z, Li J, et al. Dengue virus is involved in insulin resistance via the downregulation of IRS-1 by inducing TNF-α secretion. Biochim Biophys Acta Mol Basis Dis. 2022 Oct;1868(10):166472. doi:10.1016/j.bbadis.2022.166472. Available from: https://www.sciencedirect.com/science/article/pii/S0925443922001430
12. 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):260-266. doi:10.18231/j.ijmmtd.2022.051. Available from: https://ijmmtd.org/archive/volume/8/issue/3/article/8775

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