Predictors and determinants of albuminuria in people with prediabetes and diabetes based on smoking status : a cross-sectional study using the UK Biobank data

Background: Smoking is attributed to both micro- and macrovascular complications at any stage of metabolic deregulation including prediabetes, particularly those who develop the disease at a young age. Current global diabetes prevention programmes appear to be glucocentric, and do not fully acknowledge the ramifications of cardiorenal risk factors in smokers. A more holistic approach is needed to prevent vascular complications in people with prediabetes and diabetes. Considering albuminuria as a surrogate marker for both micro- and macrovascular complications, we investigated the relationship between smoking status and albuminuria in people with prediabetes and diabetes, and explored how this relationship is affected by age, antihypertensive, and cholesterol-lowering medications.

Methods: A logistic regression model was fitted on UK Biobank dataset with 502,490 participants. A subgroup analysis investigated the effect of age, smoking status, antihypertensive and cholesterol-lowering medications on this relationship in people with prediabetes and diabetes.

Findings: Compared with non-smokers, the odds of albuminuria in smokers with prediabetes and diabetes were 1.43 (95% CI 1.16 - 1.77), and 1.29 (95% CI 1.02 – 1.64), respectively. People younger than 50 with prediabetes, and diabetes were at increased risk of albuminuria, compared with those over 50 years old, with OR 1.62 and 1.34, respectively. The odds of albuminuria remained statistically significantly high, in prediabetes and diabetes groups, despite being on anti-hypertensive, and cholesterol-lowering medications. The odds of albuminuria were not attenuated in ex-smokers either with prediabetes or diabetes.

Interpretation: Smokers with prediabetes are at a higher risk of albuminuria than those with diabetes. The risk in ex-smokers did not decline to a statistically significant level, presumably due to insufficient lag period since quitting. Current strategies for cholesterol and hypertension management may not be sufficient to reduce the risk of albuminuria in people both with prediabetes and diabetes. Smoking cessation and continued abstinence in people with prediabetes and diabetes should be promoted in order to prevent future vascular complications. Screening for albuminuria should be incorporated in the NHS health check.