A large observational study found that caffeine may reduce the risk of death by nearly 25% for people with chronic kidney disease, even after considering other factors such as age, gender, race, smoking, other diseases, and diet.
An inverse relationship between coffee consumption and mortality has been reported in the general population. However, the association between caffeine consumption and mortality for people with chronic kidney disease remains uncertain.
The researchers hypothesised that caffeine consumption might be associated with lower mortality among participants with chronic kidney disease.
The possible protective effect of caffeine might be related with effects at vascular level as caffeine is known to promote the release of substances, such as nitric oxide, that improve the function of the vessel.
About 89% of the adult US population consumes caffeine daily. Approximately 14% of adults in the US have chronic kidney disease. Chronic kidney disease is associated with increased health care costs and a higher risk of death. The prevalence of the disease is expected to continue to increase worldwide.
The study involved data from 4,863 American people observed from 1999 to 2010. Compared with people who consumed a smaller amount of caffeine-containing beverages, caffeine consumers were more likely to be male, non-Hispanic white, have a higher education level and higher annual income, be current or former smokers, have higher alcohol consumption, and have fewer previous strokes.
The results of the analysis suggest an inverse association between caffeine consumption and all-cause mortality among participants with chronic kidney disease. Comparing with people that consumed less caffeine, patients that consumed higher levels of caffeine presented a nearly 25% reduction in the risk of death over a median follow-up of 60 months.
According to Miguel Bigotte Vieira, one of the study’s lead authors at the Centro Hospitalar Lisboa Norte, Lisbon, Portugal: “Our study showed a protective effect of caffeine consumption among patients with chronic kidney disease. The reduction in mortality was present even after considering other important factors such as age, gender, race, smoking, other diseases, and diet. These results suggest that advising patients with kidney disease to drink more caffeine may reduce their mortality. This would represent a simple, clinically beneficial, and inexpensive option, though this benefit should ideally be confirmed in a randomised clinical trial.”
The authors emphasised that this observational study cannot prove that caffeine reduces the risk of death in patients with chronic kidney disease, but only suggests the possibility of such a protective effect.
Background: An inverse relationship between coffee consumption and mortality has been reported in the general population. However, the association between caffeine consumption and mortality in patients with chronic kidney disease (CKD) remains uncertain.
Methods: We analysed 4863 non-institutionalized USA adults with CKD [defined by an estimated glomerular filtration rate (eGFR) of 15–60 mL/min/1.73 m2 and/or a urinary albumin:creatinine ratio >30 mg/g] in a nationwide study using the National Health and Nutrition Examination Survey (NHANES) 1999–2010. Caffeine consumption was evaluated by 24-h dietary recalls at baseline and all-cause, cardiovascular and cancer mortality were evaluated until 31 December 2011. We also performed an analysis of caffeine consumption according to its source (coffee, tea and soft drinks). Quartiles of caffeine consumption were <28.2 mg/day (Q1), 28.2–103.0 (Q2), 103.01–213.5 (Q3) and >213.5 (Q4).
Results: During a median follow-up of 60 months, 1283 participants died. Comparing with Q1 of caffeine consumption, the adjusted hazard ratio for all-cause mortality was 0.74 [95% confidence interval (CI) 0.60–0.91] for Q2, 0.74 (95% CI 0.62–0.89) for Q3 and 0.78 (95% CI 0.62–0.98) for Q4 (P = 0.02 for trend across quartiles). There were no significant interactions between caffeine consumption quartiles and CKD stages or urinary albumin:creatinine ratio categories regarding all-cause mortality.
Conclusions: We detected an inverse association between caffeine consumption and all-cause mortality among participants with CKD.
Miguel Bigotte Vieira, Rita Magriço, Catarina Viegas Dias, Lia Leitão, João Sérgio Neves