Cardiorespiratory Fitness and Mortality in Patients Aged 60 to 90 Years.

Chronological age alone does not fully reflect a patient's prognosis. We sought to assess the association of cardiorespiratory fitness (quantified by METs) with all-cause mortality among patients aged 60 to 90 years. This retrospective study included patients who underwent exercise treadmill testing at an integrated healthcare system from 2011 to 2019. Patients were categorized into age groups: 60 to <70 years, 70 to <80 years, and 80 to 90 years; and cardiorespiratory fitness level: low (<5 METs), moderate (5 to 10 METs), and high fitness (>10 METs). Mean follow-up was 3.5 years. A total of 40,520 patients were included (mean age 67.7 ± 4.7 years, 48.6% women). Of whom, 27,021 were 60 to <70 years old (66.7%); 12,638 70 to <80 years old (31.2%); and 1,861 80 to 90 years old (4.6%). There were 3,494 patients categorized as low (8.6%), 21,863 as moderate (54%), and 15,163 as high fitness (37.4%). Low fitness level was independently associated with lower survival (hazard ratio [HR] 1.61, 95% confidence interval [CI] 1.15 to 2.24). Using age 60 to 70 group with high fitness level as reference, the age 80 to 90 group with high fitness level had better survival than their younger counterparts with low fitness level (age 80 to 90 years high fitness level: HR 2.9, 95% CI 1.2 to 7.2; age 60 to 70 years low fitness level: HR 4.3, 95% CI 3.1 to 5.9; age 70 to 80 years low fitness level: HR 6.8, 95% CI 5.2 to 8.9) on adjusted analysis. In conclusion, higher cardiorespiratory fitness is associated with better survival. Patients >80 years old with high fitness level have comparable or even better survival than their younger counterparts with submoderate fitness levels. Chronological age alone should not be the only factor when considering prognosis.

Accuracy of common proton density fat fraction thresholds for magnitude- and complex-based chemical shift-encoded MRI for assessing hepatic steatosis in patients with obesity.

PURPOSE: MRI proton density fat fraction (PDFF) can be calculated using magnitude (MRI-M) or complex (MRI-C) MRI data. The purpose of this study was to identify, assess, and compare the accuracy of common PDFF thresholds for MRI-M and MRI-C for assessing hepatic steatosis in patients with obesity, using histology as reference. METHODS: This two-center prospective study included patients undergoing MRI-C- and MRI-M-PDFF estimations within 3 days before weight loss surgery. Liver biopsy was performed, and histology-determined steatosis grades were used as reference standard. Using receiver operating characteristics (ROC) analysis on data pooled from both methods, single common thresholds for diagnosing and differentiating none or mild (0-1) from moderate to severe steatosis (2-3) were selected as the ones achieving the highest sensitivity while providing at least 90% specificity. Selection methods were cross-validated. Performances were compared using McNemar's tests. RESULTS: Of 81 included patients, 54 (67%) had steatosis. The common PDFF threshold for diagnosing steatosis was 5.4%, which provided a cross-validated 0.88 (95% CI 0.77-0.95) sensitivity and 0.92 (0.75-0.99) specificity for MRI-M and 0.87 sensitivity (0.75-0.94) with 0.81 (0.61-0.93) specificity for MRI-C. The common PDFF threshold to differentiate steatosis grades 0-1 from 2 to 3 was 14.7%, which provided cross-validated 0.86 (95% CI 0.59-0.98) sensitivity and 0.95 (0.87-0.99) specificity for MRI-M and 0.93 sensitivity (0.68-0.99) with 0.97(0.89-0.99) specificity for MRI-C. CONCLUSION: If independently validated, diagnostic thresholds of 5.4% and 14.7% could be adopted for both techniques for detecting and differentiating none to mild from moderate to severe steatosis, respectively, with high diagnostic accuracy.