Discussion
obesity, BP reduction, diabetes, hypertensive, hypotensive syncope
OBESITY, ADVERSE EVENTS, DIABETES, SECONDARY, HYPOTENSIVE SYNCOPE
The ADAMPA trial assessed the effectiveness of an intervention combining home blood pressure self-monitoring plus self-titration of antihypertensive medication (based on an individualized pre-arranged plan) and educational components versus usual care (also with educational components) in poorly controlled hypertensive patients. Our study did not show differences in the reduction of systolic blood pressure at 12 months (primary outcome) for the self-management intervention as compared to an educational-only intervention; however, the percentage of patients achieving good control at 12 months was higher in the intervention group compared to controls. Subgroup analyses for the primary outcome measure, though underpowered, showed consistent results, suggesting greater reductions in high-risk patients such as people with diabetes or with SBP above 160 mmHg. There was no evidence of between-group differences in adverse events, health services utilization, health-related quality of life, or behavioral changes, except for a reduction of the proportion of sedentary people in the intervention group (albeit with no differences with the control group at 12 months’ follow-up).Several systematic reviews have assessed home blood pressure monitoring, although results have been heterogeneous, in part due to the combination with other co-interventions.The absolute adjusted mean difference in BP (−2.9 mmHg for SBP and −1.9 mmHg for DBP) found in the ADAMPA trial falls in the lower range of similar studies,Because no other relevant changes were detected, the effect of self-monitoring may have been mediated by the intensification of antihypertensive medication, arising from doctors’ and patients’ sharpened awareness of individualized BP targets, the regular home monitoring of their attainment, and the self-adjustment of treatment in response to high BP values (in fact, additional to the medication changes made by the physicians as part of their routine clinical practice, 58% of patients self-adjusted their medication at least once without any additional contact with their family doctor). In this sense, the intervention would act mainly by reducing therapeutic inertiaRegarding secondary outcomes, we did not find differences between groups at 12 months in smoking, obesity, or sedentarism. We likewise found no differences in the use of health services, although this result is mediated by its context within a clinical trial with planned visits (for example, patients in the intervention group had to go to the practice in the following weeks after each treatment self-adjustment). In any case, and in addition to an extension of the follow-up to 24 months, we have planned qualitative studies (focus groups with doctors, nurses, and patients) and utilization studies (including aspects of inertia, adherence, and cost-effectiveness) based on data obtained from the electronic medical record, which may broaden our knowledge about the effectiveness, acceptability, and mechanisms of action of the intervention evaluated in our context.Finally, the intervention was not associated with an increase in adverse events. Nevertheless, the frequency of hypotensive syncope seemed higher in the intervention group, although the extremely low figures do not allow for comparisons between groups. This should be further studied in larger trials.The ADAMPA trial has some limitations. First, we had to stop recruiting patients prematurely for reasons unrelated to the study. Although the sample size obtained was sufficient to detect significant differences in the main analysis, the limited sample size reduces the accuracy of the estimates. Second, the ADAMPA trial is a non-masked study wherein both the patients and the research team knew the assigned group, enabling the presence of information biases such as the Hawthorne effect (patients modifying their behavior in response to their awareness of being observed), social desirability bias (patients overreporting positive behaviors or underreporting undesirable ones), and performance bias (physicians modifying their behavior). Third, throughout the study, doctors became familiar with the components of the intervention, and it is possible that they extended some of these components (e.g., fixing individualized BP targets) to the control group; this contamination bias would tend to skew the intervention effect towards the null. Fourth, the ADAMPA trial was underpowered to detect differences in clinical outcomes, but BP reduction is an excellent surrogate endpoint in hypertensive patients and is very well correlated with reductions in morbidity and cardiovascular mortality.