title: Systematic review and meta-analysis of the prevalence of resistant hypertension in treated hypertensive populations.
abstract: BACKGROUND
  Although treatment-resistant hypertension (RH) is a serious burden on population health, there exists uncertainty about its prevalence. Hence, the objectives of this work were to systematically review and critically appraise the literature and to conduct a meta-analysis on the prevalence of RH in treated hypertensive populations.
  
  
  METHODS
  PubMed, Cochrane Library, CRD York databases, and study bibliographies were systematically searched for observational and interventional studies that report disease frequency in adult populations. The pooled prevalence was obtained through random-effect modeling. Furthermore, quality assessment, publication bias diagnostics, meta-regression, subgroup analysis by sex, and sensitivity analysis were performed.
  
  
  RESULTS
  Out of 318 retrieved studies, 20 observational studies and 4 randomized control trials (RCTs) with a total population of 961,035 were included. The random-effect method for observational studies and RCTs yielded RH prevalence ratios of 13.72% (95% confidence interval (CI) = 11.19%-16.24%) and 16.32% (95% CI = 10.68%-21.95%), respectively. Yet, most studies were incapable of ruling out pseudo-resistance caused by white-coat effect, poor medication adherence, and suboptimal dosing. Differences in RH prevalence by sex were negligible. Meta-regression analysis showed that study-level characteristics had no statistically significant influence on RH prevalence. The inclusion of further studies in the sensitivity analysis concurred with the baseline results (13.19%; 95% CI = 10.89%-15.49%).
  
  
  CONCLUSIONS
  Researchers should enhance comparability of future empirical evidence through homogeneous methodologies and comparable baseline populations. This meta-analysis concludes that RH is a frequent phenomenon and further harmonization in terms of RH definition and measurement would be necessary to clearly distinguish true treatment resistance from pseudo-resistance.
authors.affiliation: Hamburg Center for Health Economics, Universität Hamburg, Hamburg, Germany; dmitrij.achelrod@uni-hamburg.de.
authors.forename: Dmitrij
authors.initials: D
authors.lastname: Achelrod
authors.affiliation: Division of Nephrology, Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Wenzel
authors.affiliation: Hamburg Center for Health Economics, Universität Hamburg, Hamburg, Germany;
authors.forename: Simon
authors.initials: S
authors.lastname: Frey
mesh_terms: D000959:Antihypertensive Agents / Q000627:therapeutic use*; D006801:Humans; D006973:Hypertension / Q000188:drug therapy / Q000453:epidemiology*; D064887:Observational Studies as Topic; D015995:Prevalence; D016032:Randomized Controlled Trials as Topic; D017211:Treatment Failure
chemical_list: D000959:Antihypertensive Agents
keywords: blood pressure; epidemiology; hypertension; meta-analysis; prevalence; refractory hypertension; resistant hypertension.