The association between insulin resistance and atrial fibrillation: A cross-sectional analysis from SPRINT (Systolic Blood Pressure Intervention Trial).

It is unclear whether metabolic syndrome (MetS) is associated with atrial fibrillation (AF) in an older population with greater cardiovascular risk, including those with chronic kidney disease. The authors investigated the association between MetS and AF in participants in SPRINT (Systolic Blood Pressure Intervention Trial). MetS was defined based on the Modified Third National Cholesterol Education Program. The baseline prevalence rate for MetS was 55%, while 8.2% of the participants had AF. In multivariate regression analyses, AF was not associated with presence of MetS in either chronic kidney disease or non-chronic kidney disease subgroups. Age, race, history of cardiovascular diseases, decreased triglycerides, decreased pulse pressure, and albuminuria remained significantly associated with AF risk. In contrast to the general population, MetS was not associated with AF in the older population with increased cardiovascular risk studied in SPRINT.

Association of Albuminuria and Estimated Glomerular Filtration Rate with Functional Performance Measures in Older Adults with Chronic Kidney Disease.

BACKGROUND: Chronic kidney disease (CKD) is increasingly common and disproportionately affects older adults. The contribution of kidney disease to the functional impairment noted in the elderly CKD population is unclear. METHODS: This is a cross-sectional analysis of a hypertensive cohort of people aged ≥75 years from the Systolic Blood Pressure Intervention Trial. We evaluated estimated glomerular filtration rate (eGFR) and urine albumin-to-creatinine ratio (UACR) as predictors of 3 measures of functional status: EuroQol-5 Dimensional (EQ-5D) score, Falls Efficacy Scale (FES) score, and gait speed. Linear regression models were used to evaluate the associations between our independent variables and outcome measures. RESULTS: Our analysis included 2,620 participants, mean age of 79.9 (4.0) years. Unadjusted models showed that lower eGFR level and higher UACR level were associated with lower EQ-5D (p < 0.001 for both) and slower gait speed (p < 0.001 for both) and worse scores on FES (p = 0.032 and p = 0.039). In the fully adjusted models, higher levels of UACR remained significantly associated with lower EQ-5D scores and slower gait speed (p = 0.011 and p = 0.002, respectively). In contrast, level of eGFR was not associated with any functional outcome measures when accounting for covariates. CONCLUSIONS: In individuals aged ≥75 years, albuminuria and eGFR were associated with impairments in physical performance and self-reported functional status; however, only the association with albuminuria remained after adjusting for relevant demographics and comorbidities. Evaluation of albuminuria may provide an additional tool for identifying older individuals at risk for functional impairment.

Recruitment strategies and challenges in a large intervention trial: Systolic Blood Pressure Intervention Trial.

BACKGROUND: The Systolic Blood Pressure Intervention Trial is a multicenter, randomized clinical trial of 9361 participants with hypertension who are ≥50 years old. The trial is designed to evaluate the effect of intensive systolic blood pressure control (systolic blood pressure goal <120 mm Hg) compared to standard control (systolic blood pressure goal <140 mm Hg) on cardiovascular events using commonly prescribed antihypertensive medications and lifestyle modification. OBJECTIVE: To describe the recruitment strategies and lessons learned during recruitment of the Systolic Blood Pressure Intervention Trial cohort and five targeted participant subgroups: pre-existing cardiovascular disease, pre-existing chronic kidney disease, age ≥75 years, women, and minorities. METHODS: In collaboration with the National Institutes of Health Project Office and Systolic Blood Pressure Intervention Trial Coordinating Center, five Clinical Center Networks oversaw clinical site selection, recruitment, and trial activities. Recruitment began on 8 November 2010 and ended on 15 March 2013 (about 28 months). Various recruitment strategies were used, including mass mailing, brochures, referrals from healthcare providers or friends, posters, newspaper ads, radio ads, and electronic medical record searches. RESULTS: Recruitment was scheduled to last 24 months to enroll a target of 9250 participants; in just over 28 months, the trial enrolled 9361 participants. The trial screened 14,692 volunteers, with 33% of initial screens originating from the use of mass mailing lists. Screening results show that participants also responded to recruitment efforts through referral by Systolic Blood Pressure Intervention Trial staff, healthcare providers, or friends (45%); brochures or posters placed in clinic waiting areas (15%); and television, radio, newspaper, Internet ads, or toll-free numbers (8%). The overall recruitment yield (number randomized/number screened) was 64% (9361 randomized/14,692 screened), 77% for those with cardiovascular disease, 79% for those with chronic kidney disease, 70% for those aged ≥75 years, 55% for women, and 61% for minorities. As recruitment was observed to lag behind expectations, additional clinics were included and inclusion criteria were broadened, keeping event rates and trial power in mind. As overall recruitment improved, a greater focus on subgroup recruitment was implemented. CONCLUSION: Systolic Blood Pressure Intervention Trial met its overall projected recruitment goal using diverse, locally adapted enrollment strategies to specifically target persons with cardiovascular disease, chronic kidney disease, ≥75 years old, women, and minority subgroups. The trial exceeded its recruitment goal for minorities but found it a challenge to meet the competing demands of the targeted goals for recruiting into the remaining four subgroups. Important lessons include the imperative to monitor the recruitment process carefully, decide early to add new clinics or modify inclusion and exclusion criteria if recruitment lags, and consider limiting enrollment to subgroups only. We found benefit in using multiple recruitment sources simultaneously; mass mailing produced the largest number of participants, but referrals resulted in the greater randomization yield.

Characterizing Frailty Status in the Systolic Blood Pressure Intervention Trial.

BACKGROUND: The Systolic Blood Pressure Intervention Trial (SPRINT) is testing whether a lower systolic blood pressure (BP) target of 120 mm Hg leads to a reduction in cardiovascular morbidity and mortality among hypertensive, nondiabetic adults. Because there may be detrimental effects of intensive BP control, particularly in older, frail adults, we sought to characterize frailty within SPRINT to address ongoing questions about the ability of large-scale trials to enroll representative samples of noninstitutionalized, community-dwelling, older adults. METHODS: We constructed a 36-item frailty index (FI) in 9,306 SPRINT participants, classifying participants as fit (FI ≤ 0.10), less fit (0.10 < FI ≤ 0.21), or frail (FI > 0.21). Recurrent event models were used to evaluate the association of the FI with the incidence of self-reported falls, injurious falls, and all-cause hospitalizations. RESULTS: The distribution of the FI was comparable with what has been observed in population studies, with 2,570 (27.6%) participants classified as frail. The median FI was 0.18 (interquartile range = 0.14 to 0.24) in participants aged 80 years and older (N = 1,159), similar to the median FI of 0.17 reported for participants in the Hypertension in the Very Elderly Trial. In multivariable analyses, a 1% increase in the FI was associated with increased risk for self-reported falls (hazard ratio [HR] = 1.030), injurious falls (HR = 1.035), and all-cause hospitalizations (HR = 1.038) (all p values < .0001). CONCLUSIONS: Large clinical trials assessing treatments to reduce cardiovascular disease risk, such as SPRINT, can enroll heterogeneous populations of older adults, including the frail elderly, comparable with general population cohorts.