Constipation and Hemodialysis, Increased Risk of Cardiovascular Events and Mortality

Is Constipation Just a Minor Digestive Issue?

Constipation and Hemodialysis, Constipation is often considered a minor digestive issue, but recent research suggests it can have serious health implications. In particular, for patients undergoing hemodialysis due to chronic kidney disease (CKD), constipation is associated with an increased risk of cardiovascular events and mortality.

A large-scale study in Korea revealed that 25.9% of hemodialysis patients suffer from constipation, and these patients face up to a 15% higher risk of cardiovascular events and death. Let’s explore the causes, consequences, and possible management strategies for constipation in dialysis patients.

📊 Study Overview: Investigating the Link Between Constipation and Cardiovascular Risk

This study utilized data from the Korean Health Insurance Review and Assessment Service (HIRA) in 2015, analyzing 35,230 hemodialysis patients to examine the correlation between constipation, cardiovascular disease, and mortality rates.

Study Design and Key Parameters:

Participants: 35,230 CKD patients undergoing hemodialysis
Definition of Constipation: Patients who were prescribed laxatives 180 times or more within a year
Outcome Measures:
- Primary Outcomes:
  - Acute ischemic stroke
  - Hemorrhagic stroke
  - Myocardial infarction
  - All-cause mortality
- Secondary Outcomes: Individual analysis of each component of the primary outcomes

📈 Study Results: Increased Cardiovascular Risk in Constipated Patients

🔹 Prevalence of Constipation in Hemodialysis Patients

According to the study, 25.9% (9,133 patients) of hemodialysis patients suffered from constipation.

🔎 Why is Constipation More Common in Dialysis Patients?
✅ Dietary Restrictions: Limited potassium and phosphorus intake reduces fiber consumption
✅ Fluid Restriction: Dialysis patients must limit fluid intake, leading to harder stools
✅ Medication Side Effects: Potassium binders, phosphate binders, and iron supplements contribute to constipation
✅ Reduced Physical Activity: Dialysis patients often have limited movement, slowing digestion

🔹 Characteristics of Constipated Patients

Patients with constipation were older and had a higher prevalence of diabetes, hypertension, and ischemic heart disease compared to those without constipation.

Characteristic	No Constipation (n=26,097)	Constipation (n=9,133)
Average Age (years)	58.8	63.7
Diabetes (%)	56.6%	72.6%
Hypertension (%)	82.9%	87.9%
Ischemic Heart Disease (%)	31.0%	40.1%
Body Mass Index (BMI)	22.3	22.6

🔎 Interpretation: Patients with constipation tend to have higher metabolic and cardiovascular risk factors, potentially exacerbating health issues.

🔹 Association Between Constipation, Cardiovascular Events, and Mortality

🔍 Key Findings After 5.4 Years of Follow-Up:
✅ Constipated patients had a 15% higher risk of cardiovascular events
✅ 16% increased risk of ischemic stroke
✅ 14% higher risk of all-cause mortality
✅ No significant association with hemorrhagic stroke or myocardial infarction

🔽 Adjusted Hazard Ratios for Cardiovascular Risk

Outcome	Model 1 (Basic Adjustments)	Model 2 (Additional Adjustments)	Model 3 (Fully Adjusted)
Total Cardiovascular Events	1.24 (1.20-1.29)	1.22 (1.17-1.26)	1.15 (1.11-1.20)
All-Cause Mortality	1.26 (1.21-1.31)	1.23 (1.18-1.28)	1.14 (1.10-1.20)
Ischemic Stroke	1.30 (1.15-1.47)	1.26 (1.11-1.42)	1.16 (1.02-1.32)

📢 In summary, constipation significantly increases the risk of cardiovascular disease and mortality in dialysis patients.

🧐 Why Does Constipation Increase Cardiovascular Risk?

1️⃣ Gut Microbiota Imbalance (Dysbiosis)

Constipation disrupts gut microbiota, reducing beneficial bacteria and increasing inflammation.
Altered gut microbiota is linked to cardiovascular diseases and metabolic disorders.
Study: Wang et al. (2011) found increased TMAO (Trimethylamine N-oxide) levels in constipated patients, a compound known to raise heart disease risk.

2️⃣ Sudden Blood Pressure Spikes (Valsalva Maneuver)

Straining during bowel movements can cause a sudden increase in blood pressure, potentially triggering strokes or heart attacks.
Study: Ishiyama et al. (2019) found a direct correlation between constipation-induced blood pressure spikes and cardiovascular events.

3️⃣ Nutritional Deficiencies & Metabolic Dysfunction

Low fiber intake and chronic constipation can lead to nutritional imbalances.
Study: Sumida et al. (2019) found that CKD patients with constipation had a higher prevalence of metabolic disorders and cardiovascular risk factors.

📢 Conclusion and Recommendations

✅ Constipation is not just a digestive problem—it significantly increases cardiovascular and mortality risks in hemodialysis patients.
✅ Proper dietary adjustments, lifestyle modifications, and medical interventions are essential to prevent complications.
✅ Further studies are needed to determine whether treating constipation can improve survival rates in dialysis patients.

🔗 Reference

Park SC, Jung J, Kwon YE, et al. Constipation and risk of death and cardiovascular events in patients on hemodialysis. Kidney Res Clin Pract 2025;44(1):155-163. DOI: 10.23876/j.krcp.24.174

Bridging CKD treatment gap : Real Solutions

Health for All