Association of chronic kidney disease with outcomes in chronic heart failure: a propensity-matched study.

BACKGROUND: Chronic kidney disease (CKD) is associated with increased mortality in patients with heart failure (HF). However, its association with hospitalization in HF patients has not been well studied. METHODS: Of 7788 patients in the Digitalis Investigation Group trial, 3527 had CKD, defined by an estimated glomerular filtration rate (GFR) <60 ml/min/1.73 m(2) body surface area (BSA). Propensity scores for CKD were calculated using a multivariable logistic regression model and used to match 2399 pairs of patients with and without CKD. Matched Cox regression analyses were used to estimate association of CKD with outcomes. RESULTS: All-cause hospitalization occurred in 1636 (rate, 4233/10,000 person-years) and 1587 (rate, 3733/10,000 person-years) patients respectively, with and without CKD (matched hazard ratio [HR] for CKD, 1.18, 95% confidence interval [CI], 1.08-1.29; P < 0.0001). Matched HR for cardiovascular and HF hospitalization were respectively 1.17 (95% CI, 1.06-1.28, P = 0.002) and 1.28 (95% CI, 1.13-1.45, P < 0.0001). Compared to GFR >or=60 ml/min/1.73 m(2) BSA, HR for all-cause hospitalization for GFR 45-59 and <45 ml/min/1.73 m(2) BSA were respectively 1.04 (95% CI, 0.94-1.16; P = 0.422) and 1.58 (95% CI, 1.34-1.87; P < 0.0001). Similarly, HR for all-cause death for GFR 45-59 and <45 ml/min/1.73 m(2) BSA were respectively 1.03 (95% CI, 0.90-1.18; P = 0.651) and 1.70 (95% CI, 1.40-2.07; P < 0.0001). Matched HR for death due to cardiovascular causes and progressive HF were respectively 1.24 (95% CI, 1.09-1.40; P = 0.001) and 1.42 (95% CI, 1.16-1.72; P = 0.001). CONCLUSION: CKD was associated with increased mortality and hospitalization in ambulatory patients with chronic HF, which increased progressively with worsening kidney function.

A propensity-matched study of low serum potassium and mortality in older adults with chronic heart failure.

OBJECTIVE: Most HF patients are older adults, yet the associations of low serum potassium and outcomes in these patients are unknown. We studied the effect of low serum potassium in a propensity-matched population of elderly HF patients. METHODS: Of the 7788 patients in the Digitalis Investigation Group trial, 4036 were >or=65 years. Of these, 3598 had data on baseline serum potassium and 324 with potassium >or=5 mEq/L were excluded. Remaining patients were categorized into low (<4 mEq/L; n=590) and normal (4-4.9 mEq/L; n=2684) potassium groups. Propensity scores for low-potassium, calculated for each patient, were used to match 561 low-potassium and 1670 normal-potassium patients. Association of low potassium and outcomes were assessed using matched Cox regression analyses. RESULTS: Patients had a mean (+/-SD) age of 72 (+/-6) years, 29% were women and 12% were non-whites. Of the 561 low-potassium patients, 500 had low-normal (3.5-3.9 mEq/L) potassium. All-cause mortality occurred in 37% (rate, 1338/10,000 person-years) normal-potassium and 43% (rate, 1594/10,000 person-years) low-potassium patients (hazard ratio {HR} for low-potassium, 1.22; 95% confidence interval {CI}, 1.04-1.44; p=0.014). Low-normal (3.5-3.9 mEq/L) potassium levels had a similar association with mortality (HR, 1.19, 95% CI, 1.00-1.41, p=0.049). Low (HR, 1.10; 95% CI, 0.96-1.25; p=0.175) or low-normal (HR=1.09, 95% CI=0.95-1.25, p=0.229) serum potassium levels were not associated with all-cause hospitalization. CONCLUSIONS: In a propensity-matched population of elderly ambulatory chronic HF patients, well-balanced in all measured baseline covariates, low and low-normal serum potassium were associated with increased mortality but had no association with hospitalization.

A propensity-matched study of outcomes of chronic heart failure (HF) in younger and older adults.

The majority of heart failure (HF) patients are older adults and most HF-related adverse events occur in these patients. However, the independent association of age and outcomes in HF is not clearly determined. We categorized 7788 ambulatory HF patients who participated in the Digitalis Investigation Group (DIG) trial as younger (< 65 years) and older (> or = 65 years). Propensity scores for older age were calculated for each patient and used to match 2381 pairs of younger and older patients. The associations of older age with mortality and hospitalization during a median 40 months of follow-up were assessed using matched Cox regression models. All-cause mortality occurred in 877 older patients versus 688 younger patients (hazard ratio when older age was compared with younger age (HR)=1.26; 95% confidence interval (CI)=1.12-1.41; p<0.0001). Older patients, when compared with propensity-matched younger patients, also had significantly higher mortality rates due to cardiovascular causes (HR=1.14; 95% CI=1.00-1.30; p=0.044) and worsening heart failure causes (HR=1.32; 95% CI=1.07-1.62; p=0.009). No significant association was found between age and hospitalization due to all causes (HR=1.08; 95% CI=0.99-1.18; p=0.084) and cardiovascular causes (HR=1.03; 95% CI=0.93-1.13; p=0.622). However, hospitalization due to HF was significantly increased in older patients (HR=1.14; 95% CI=1.01-1.28; p=0.041). In ambulatory HF patients, older age although associated with increased mortality, was not associated with increased hospitalizations except for those due to worsening HF.

Association of diuretic use and overactive bladder syndrome in older adults: a propensity score analysis.

Diuretic use and overactive bladder syndrome are common in older adults. However, the relationship between the two has not been well studied. Data were collected by self-administered questionnaires including the Urge Urinary Distress Inventory (Urge-UDI) and the Urge Incontinence Impact Questionnaire (Urge-IIQ), and by outpatient chart abstraction. Patients (n=172) had a mean age of 79+/-7.5 (+/-S.D.), 76% were women, and 48% were African Americans; 76% had hypertension, 32% had heart failure, and 66% were receiving diuretics (57% loop diuretics). Overall, 72%, 68%, and 73% of patients, respectively, reported urinary frequency, urgency and urge incontinence. Diuretic use was associated with increased frequency (81% versus 55% non-diuretic; odds ratio (OR)=3.48; 95% confidence interval (CI)=1.73-7.03) and urgency (74% versus 57% non-diuretic; OR=2.17; 95% CI=1.11-4.24) but not with incontinence (OR=1.74; 95% CI=0.87-3.50). When adjusted for propensity scores, diuretic use had independent associations with frequency (adjusted OR=3.09; 95% CI=1.20-7.97) and urgency (adjusted OR=2.50; 95% CI=1.00-6.27). In addition to frequency and urgency, loop diuretic use was also associated with incontinence (OR=2.54; 95% CI=1.09-5.91), which lost significance after propensity adjustment (adjusted OR=1.88; 95% CI=0.57-6.17). Overall summary mean Urge-IIQ score was 1.83+/-0.85 with 1.75+/-0.86, 1.68+/-0.76, and 2.03+/-0.88, respectively, for no diuretic, non-loop, and loop-diuretic patients (one-way analysis of variance (ANOVA) p=0.063). Overactive bladder symptoms were common among ambulatory older adults and were associated with diuretic use, and had stronger associations with loop diuretic use.