Controlling Nutritional Status (CONUT) score as a predictor of all-cause mortality in elderly hypertensive patients: a prospective follow-up study

OBJECTIVES: The aim of this study was to elucidate the impact of nutritional status on survival per Controlling Nutritional Status (CONUT) score and Geriatric Nutritional Risk Index (GNRI) in patients with hypertension over 80 years of age. DESIGN: Prospective follow-up study. PARTICIPANTS: A total of 336 hypertensive patients over 80 years old were included in this study. OUTCOME MEASURES: All-cause deaths were recorded as Kaplan-Meier curves to evaluate the association between CONUT and all-cause mortality at follow-up. Cox regression models were used to investigate the prognostic value of CONUT and GNRI for all-cause mortality in the 90-day period after admission. RESULTS: Hypertensive patients with higher CONUT scores exhibited higher mortality within 90 days after admission (1.49%, 6.74%, 15.38%, respectively, χ(2)=30.92, p=0.000). Surviving patients had higher body mass index (24.25±3.05 vs 24.25±3.05, p=0.012), haemoglobin (123.78±17.05 vs 115.07±20.42, p=0.040) and albumin levels, as well as lower fasting blood glucose (6.90±2.48 vs 8.24±3.51, p=0.010). Higher GRNI score (99.42±6.55 vs 95.69±7.77, p=0.002) and lower CONUT (3.13±1.98 vs 5.14±2.32) both indicated better nutritional status. Kaplan-Meier curves indicated that survival rates were significantly worse in the high-CONUT group compared with the low-CONUT group (χ(1) =13.372, p=0.001). Cox regression indicated an increase in HR with increasing CONUT risk (from normal to moderate to severe). HRs (95% CI) for 3-month mortality was 1.458 (95% CI 1.102 to 1.911). In both respiratory tract infection and ‘other reason’ groups, only CONUT was a sufficiently predictor for all-cause mortality (HR=1.284, 95% CI 1.013 to 1.740, p=0.020 and HR=1.841, 95% CI 1.117 to 4.518, p=0.011). Receiver operating characteristic showed that CONUT higher than 3.0 was found to predict all-cause mortality with a sensitivity of 77.8% and a specificity of 64.7% (area under the curve=0.778, p<0.001). CONCLUSION: Nutritional status assessed via CONUT is an accurate predictor of all-cause mortality 90 days postadmission. Evaluation of nutritional status may provide additional prognostic information in hypertensive patients.