Effects of Intensive Blood Pressure Control in Patients with and without Albuminuria: Post Hoc Analyses from SPRINT

BACKGROUND AND OBJECTIVES

It is unclear whether the presence of albuminuria modifies the effects of intensive systolic BP control on risk of eGFR decline, cardiovascular events, or mortality.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The Systolic Blood Pressure Intervention Trial randomized nondiabetic adults ≥50 years of age at high cardiovascular risk to a systolic BP target of <120 or <140 mm Hg, measured by automated office BP. We compared the absolute risk differences and hazard ratios of ≥40% eGFR decline, the Systolic Blood Pressure Intervention Trial primary cardiovascular composite outcome, and all-cause death in those with or without baseline albuminuria (urine albumin-creatinine ratio ≥30 mg/g).

RESULTS

Over a median follow-up of 3.1 years, 69 of 1723 (4%) participants with baseline albuminuria developed ≥40% eGFR decline compared with 61 of 7162 (1%) participants without albuminuria. Incidence rates of ≥40% eGFR decline were higher in participants with albuminuria (intensive, 1.74 per 100 person-years; standard, 1.17 per 100 person-years) than in participants without albuminuria (intensive, 0.48 per 100 person-years; standard, 0.11 per 100 person-years). Although effects of intensive BP lowering on ≥40% eGFR decline varied by albuminuria on the relative scale (hazard ratio, 1.48; 95% confidence interval, 0.91 to 2.39 for albumin-creatinine ratio ≥30 mg/g; hazard ratio, 4.55; 95% confidence interval, 2.37 to 8.75 for albumin-creatinine ratio <30 mg/g; P value for interaction <0.001), the absolute increase in ≥40% eGFR decline did not differ by baseline albuminuria (incidence difference, 0.38 events per 100 person-years for albumin-creatinine ratio ≥30 mg/g; incidence difference, 0.58 events per 100 person-years for albumin-creatinine ratio <30 mg/g; P value for interaction =0.60). Albuminuria did not significantly modify the beneficial effects of intensive systolic BP lowering on cardiovascular events or mortality evaluated on relative or absolute scales.

CONCLUSIONS

Albuminuria did not modify the absolute benefits and risks of intensive systolic BP lowering.

The design of an observational study of hypertension management, adherence and pressure control in Blood Pressure Success Zone Program participants

AIMS

The Blood Pressure Success Zone (BPSZ) Program, a nationwide initiative, provides education in addition to a complimentary trial of one of three antihypertensive medications. The BPSZ Longitudinal Observational Study of Success (BPSZ-BLISS) aims to evaluate blood pressure (BP) control, adherence, persistence and patient satisfaction in a representative subset of BPSZ Program participants. The BPSZ-BLISS study design is described here.

METHODS

A total of 20,000 physicians were invited to participate in the study. Using a call centre supported Interactive Voice Response System (IVRS), physicians report BP and other data at enrolment and every usual care visit up to 12 +/- 2 months; subjects self-report BPs, persistence, adherence and treatment satisfaction at 3, 6 and 12 months post-BPSZ Program enrolment. In addition to BPSZ Program enrolment medications, physicians prescribe antihypertensive medications and schedule visits as per usual care. The General Electric Healthcare database will be used as an external reference.

RESULTS

After 18 months, over 700 IRB approved physicians consented and enrolled 10,067 eligible subjects (48% male; mean age 56 years; 27% newly diagnosed); 97% of physicians and 78% of subjects successfully entered IVRS enrolment data. Automated IVRS validations have maintained data quality (< 5% error on key variables). Enrolment was closed 30 April 2007; study completion is scheduled for June 2008.

CONCLUSIONS

The evaluation of large-scale health education programmes requires innovative methodologies and data management and quality control processes. The BPSZ-BLISS design can provide insights into the conceptualisation and planning of similar studies.

Predicting completion of treatment among foreign-born adolescents treated for latent tuberculosis infection in Los Angeles

SETTING

Two health clinics in Los Angeles County, California.

OBJECTIVE

To identify factors associated with completion of care among foreign-born adolescents treated for latent tuberculosis infection (LTBI).

DESIGN

A total of 766 low-income adolescents (79% participation rate), including 610 foreign-born, were recruited. In prospective face-to-face interviews, data were obtained on socio-demographic and lifestyle characteristics, psychosocial factors and clinic-related variables. Medical chart data were abstracted regarding clinic appointment keeping and completion of treatment. Univariate and multivariate logistic regression analyses were performed to identify factors associated with completion of care.

RESULTS

Foreign-born adolescents were more likely to complete care than US-born adolescents, with 82% completion of care rate. In logistic regression analyses after controlling for age, medication taking behavior (OR 1.26, 95%CI 1.15-1.39), living with both parents (OR 1.74, 95%CI 1.02-2.97), sexual intercourse (OR 0.66, 95%CI 0.36-1.19) and speaking mostly or only English with parents (OR 0.39, 95%CI 0.15-1.03) were independently associated with completion of care.

CONCLUSION

These findings contribute to our understanding of the factors that may explain why some adolescents complete care whereas others do not. They provide supportive evidence that tailored intervention programs should be developed to support the screening and completion of treatment of foreign-born adolescents.