Is constipation associated with hypertension and cardiovascular events in older Australian adults?

By Dr. Chinta SidharthanReviewed by Danielle Ellis, B.Sc.Jul 11 2023

In a recent study published in Scientific Reports, scientists investigated the association between constipation and cardiovascular events such as angina, myocardial infarction, transient ischemic attack, and stroke, as well as hypertension among a representative population of elderly hospitalized patients in Australia.

Background

Cardiovascular disease is one of the major health problems worldwide, with a staggering mortality rate that continues to grow. Over the last 30 years, the incidence of cardiovascular diseases has doubled despite attempts to address the modifiable risk factors of cardiovascular disease through pharmaceutical and lifestyle interventions.

Close to 32% of global mortality is attributed to cardiovascular events, of which stroke or myocardial infarction constitute 85% of the cases. Hypertension is one of the prevalent risk factors for cardiovascular disease, with a higher incidence among older adults than among young people.

Constipation, common among the elderly, is believed to be linked to hypertension. While studies among the Japanese population and veterans in the United States have reported an association between constipation and an increased risk of ischemic stroke, coronary heart disease, and mortality due to stroke and other cardiovascular events, it remains unclear whether constipation is independently associated with cardiovascular events or hypertension.

About the study

In the present study, the researchers conducted a matched-cohort analysis among elderly Australian hospitalized patients, with half of the study population having constipation. The average age of the cohorts was 73.7 years, and of the patients who had constipation, close to half had hypertension, while close to 70% of the patients who had hypertension also suffered from constipation.

The data from the Department of Health and Human Services of Victoria, Australia, were used for the analyses and comprised hospitalization information from all private and public hospitals in Victoria. After applying exclusion criteria based on factors such as age and occurrence of the measured study outcomes, the final dataset consisted of 541,172 hospitalized patients, of whom 50% had constipation.

The study examined cardiovascular events, including stroke, angina, transient ischemic attack, and myocardial infarction, which were diagnosed according to the tenth revision of the International Classification of Diseases.

Data were also obtained on covariates that could be potentially confounding, such as age, sex, smoking behavior, obesity, diabetes status, hypertension, sleep apnea, chronic obstructive pulmonary disease, endocrine disorders, kidney disease, metabolic disorders, peripheral occlusive arterial disease, irritable bowel syndrome, gastrointestinal disorders, cardiac arrythmia, atrial fibrillation, ulcerative colitis, Crohn’s disease, and socioeconomic status.

Binary logistic models were used to evaluate the association between constipation and cardiovascular events, and hypertension while controlling for the various covariates. Subgroup analyses were conducted across groups based on sex or hypertension. Additionally, binary logistic regression was used to determine the role of the interaction between hypertension and constipation in modifying the risk of cardiovascular disease.

Results

The results indicated that the multivariate-adjusted risk for cardiovascular events and hypertension was higher for patients with constipation as compared to those without constipation.

Furthermore, when compared to patients who did not have constipation or hypertension, the risk for cardiovascular events after adjusting for all the covariates was higher among patients with only constipation or only hypertension. Moreover, the cardiovascular event risk when all events were considered appeared to be additive among patients with both hypertension and constipation.

The scientists discussed some of the potential mechanisms that could explain the association between constipation, hypertension, and cardiovascular events. One of the mechanisms linking constipation and hypertension is the increase in water absorption from the intestines during constipation, which could result in hypertension due to the increase in blood volume.

Based on growing evidence from research on the role of gut microbiomes in the pathophysiology of various diseases, the researchers believe that another mechanism through which constipation is linked to hypertension and cardiovascular disease is gut microbiome dysbiosis leading to inflammation and alterations in the production of short-chain fatty acids.

Early studies on constipation have reported that obstruction of the intestines results in bacterial overgrowth in the region of the gut above the obstruction, while normal gut bacterial communities are found in the region below the obstruction. Gut microbiome dysbiosis due to constipation is also thought to be independently associated with the increased risk of cardiovascular events such as myocardial infarction.

Conclusions

To summarize, the study explored the association between constipation and increased risk of cardiovascular events and hypertension in elderly adults in Australia.

The findings indicated that constipation is associated with a higher risk of cardiovascular events and hypertension in adults over 60 years, with the risk of all cardiovascular events increasing additively in individuals with both constipation and hypertension. The results highlight the need to address constipation as a modifiable risk factor to reduce the incidence of cardiovascular events.