Structured hypertension care: VIPER lacks real bite

Nov 29 2012

By Caroline Price, Senior medwireNews Reporter

An intensive structured care program for hypertension management in primary care leads to some improvements in blood pressure control, results from the VIPER-BP trial show.

As reported in a paper in the BMJ, patients who received the structured care intervention, involving computerized risk profiling and titration of antihypertensive therapy to the needs of individual patients, were 1.3 times as likely to achieve their individual blood pressure target over the 26-week study period as those who received usual care.

However, the VIPER-BP (Valsartan Intensified Primary carE Reduction of Blood Pressure) investigators concede that still only a small fraction of participants achieved these more stringent blood pressure targets. Indeed, the standard goal of 140/90 mmHg was much more readily attained in both arms of the study.

"Given the intensity of the intervention and facilitated pathways to higher doses of combination antihypertensive treatment, these data highlight critical questions around the application of more stringent blood pressure targets in high-risk people - that is, those with established cardiovascular disease or renal disease," write the authors, led by Simon Stewart from Baker IDI Heart and Diabetes Institute in Melbourne, Australia.

"The results are particularly relevant to clinicians when clinical guidelines and health policies seek to apply expert recommendations that may not be truly achievable."

The study was performed in Australia and included 1562 patients, recruited from a variety of general practices located across the whole country. None of the patients had achieved goal blood pressure after a 28-day run-in period on antihypertensive monotherapy (valsartan 80 mg daily).

All the participants underwent the clinical risk profiling at baseline. Those assigned to intervention after the run-in period followed an intensive stepped program, with mandatory visits to their general practitioner at weeks 6, 10, 14, and 18 to review their blood pressure and adjust treatment according to their prespecified algorithms.

Overall, 36.2% of patients in the intervention arm achieved their individual target blood pressure by 26 weeks, compared with 27.4% in the usual care arm, giving an 8.8% absolute difference and a significant relative risk of 1.28.

Nearly two-thirds (63.5%) in the intervention arm achieved the "classic" blood pressure target of 140/90 mmHg, compared with just over half (54.0%) of the usual care group (relative risk=1.18).

Among 1141 patients with complete risk profiling data before and after randomization, the intervention group had greater reductions in cardiovascular risk scores, and the proportion at high risk (>15% 5-year risk) fell from 41.2% to 25.6% in this group, compared with a reduction from 40.2% to 30.1% in the usual care group.

In an accompanying editorial, Christopher Clark, from University of Exeter, and Richard McManus, from University of Oxford, in the UK, say that increased prescription rates and drug side effects observed in the intervention arm suggest "some success in overcoming clinical inertia."

However, they also question whether attaining lower blood pressure targets is realistic, or advisable, in primary care - and indeed whether it would be cost-effective, given structured care required patients to be seen twice as often as usual.

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