Associations between controlling nutritional status and mortality in osteoporosis: evidence from NHANES, 2005-2018

Malnutrition and immune dysregulation are common in patients with osteoporosis but are often overlooked and may contribute to poor outcomes. The Controlling Nutritional Status (CONUT) score is a simple instrument reflecting both nutritional and immune status, but its prognostic value in osteoporosis remains unclear. This retrospective, observational study included data of adults aged ≥ 50 years with osteoporosis extracted from five two-year cycles of the National Health and Nutrition Examination Survey (NHANES; 2005-2006, 2007-2008, 2009-2010, 2013-2014, and 2017-2018). Osteoporosis was defined as femoral neck T-score < - 2.5. CONUT scores were calculated from participants' serum albumin, total cholesterol, and total lymphocyte count, and high CONUT was defined as ≥ 2. All-cause and cardiovascular disease (CVD)-related mortality through December 31, 2019, was ascertained via the National Death Index. Weighted Cox regression models were used to estimate hazard ratios (HRs) for mortality outcomes. Among 871 participants representing 5.86 million US adults with osteoporosis, 40.7% had high CONUT scores. During a median follow-up of 9.8 years, high CONUT scores were associated with increased all-cause mortality (53.2% vs. 30.9%, p < 0.001) and CVD mortality (17.6% vs. 8.2%, p < 0.001). In multivariable analysis, after adjustments for possible confounders, high CONUT scores were independently associated with higher all-cause (HR 1.64; 95% CI 1.25-2.14) and CVD mortality (HR 1.91; 95% CI 1.15-3.19). Associations with all-cause mortality were consistent across sex, diabetes, and CKD subgroups and associations with CVD mortality were most pronounced among females and patients with diabetes. The CONUT scores may help identify high-risk individuals, particularly those with greater comorbidity burden, who may benefit from closer monitoring and more comprehensive nutritional assessment.