Endocrine Abstracts

Introduction: Metabolic syndrome (MS) is related with progressive decrease of renal function. Although hypertension has a major role on this relationship, it is not clear how its behavior is related to decreased renal function.

Objective: To study how blood pressure (BP) measured by 24-hour ambulatory BP is related to renal function in patients with and without MS.

Methods: We designed a cross-sectional study of consecutive individuals (n=108; females 74%; 52.8±12.7 years; mean±S.D.) from the diabetes clinic of a university hospital. Patients were classified according to their BP behavior: normotension (NT; n=29), white-coat hypertension (WCH; n=19) and ambulatory hypertension (AHT; n=57). Fasting and 2 h-plasma glucose levels, lipid profile, creatinine and 24-h urinary albumin excretion (UAER) were measured. Glomerular filtration rate (GFR) was estimated by the CKD-EPI equation. A two-sided P value <0.05 was considered significant.

Results: Estimated GFR (EGFR) was lower in subjects with MS than in those without MS (Mean±S.D.; 90±20 vs 98.8±16.5; P=0.047). EGFR was related to age (r=−0.666; P<0.001), fasting glucose (r=0.223; P=0.021), and 24-h systolic BP (r=−0.196; P=0.044), but not to diastolic BP. EGFR was inversely related to sleep-time BP (r=−0.224; P=0.021), morning systolic BP (r=−0.224; P=0.030) and pulse pressure (r=−0.233; P=0.170). Subjects with WCH and AHT compared to those with NT had lower EGFR (Mean±S.D.; 89.3±18 vs 89.6±26.3 vs 100.2±14.8; P=0.036) and higher UAER (Median [P25–75]; 1 [0–5.3] vs 6.1 [1–19] vs 6.3 [1–16.8]; P=0.031).

Conclusion: A higher sleep-time BP, morning systolic BP, and pulse pressure were the components of BP homeostasis mostly related to decreased renal function and may be taken into account in the assessment of subjects with MS. The findings should prompt further research in order to evaluate whether or not interventions impacting on BP during sleep-time and early morning period may prevent renal damage.