Does This Patient Have Acute Mountain Sickness?: The Rational Clinical Examination Systematic Review.

Acute mountain sickness (AMS) affects more than 25% of individuals ascending to 3500 m (11 500 ft) and more than 50% of those above 6000 m (19 700 ft). AMS may progress from nonspecific symptoms to life-threatening high-altitude cerebral edema in less than 1% of patients. It is not clear how to best diagnose AMS. To systematically review studies assessing the accuracy of AMS diagnostic instruments, including the visual analog scale (VAS) score, which quantifies the overall feeling of sickness at altitude (VAS[O]; various thresholds), Acute Mountain Sickness-Cerebral score (AMS-C; ≥0.7 indicates AMS), and the clinical functional score (CFS; ≥2 indicates AMS) compared with the Lake Louise Questionnaire Score (LLQS; score of ≥5). Searches of MEDLINE and EMBASE from inception to May 2017 identified 1245 publications of which 91 were suitable for prevalence analysis (66 944 participants) and 14 compared at least 2 instruments (1858 participants) using a score of 5 or greater on the LLQS as a reference standard. To determine the prevalence of AMS for establishing the pretest probability of AMS, a random-effects meta-regression was performed based on the reported prevalence of AMS as a function of altitude. AMS prevalence, likelihood ratios (LRs), sensitivity, and specificity of screening instruments. The final analysis included 91 articles (comprising 66 944 study participants). Altitude predicted AMS and accounted for 28% of heterogeneity between studies. For each 1000-m (3300-ft) increase in altitude above 2500 m (8200 ft), AMS prevalence increased 13% (95% CI, 9.5%-17%). Testing characteristics were similar for VAS(O), AMS-C, and CFS vs a score of 5 or greater on the LLQS (positive LRs: range, 3.2-8.2; P = .22 for comparisons; specificity range, 67%-92%; negative LRs: range, 0.30-0.36; P = .50 for comparisons; sensitivity range, 67%-82%). The CFS asks a single question: "overall if you had any symptoms, how did they affect your activity (ordinal scale 0-3)?" For CFS, moderate to severe reduction in daily activities had a positive LR of 3.2 (95% CI, 1.4-7.2) and specificity of 67% (95% CI, 37%-97%); no reduction to mild reduction in activities had a negative LR of 0.30 (95% CI, 0.22-0.39) and sensitivity of 82% (95% CI, 77%-87%). The prevalence of acute mountain sickness increases with higher altitudes. The visual analog scale for the overall feeling of sickness at altitude, Acute Mountain Sickness-Cerebral, and clinical functional score perform similarly to the Lake Louise Questionnaire Score using a score of 5 or greater as a reference standard. In clinical and travel settings, the clinical functional score is the simplest instrument to use. Clinicians evaluating high-altitude travelers who report moderate to severe limitations in activities of daily living (clinical functional score ≥2) should use the Lake Louise Questionnaire Score to assess the severity of acute mountain sickness

Does This Adult Patient Have Hypertension?: The Rational Clinical Examination Systematic Review

Importance: Office blood pressure (BP) measurements are not the most accurate method to diagnose hypertension. Home BP monitoring (HBPM) and 24-hour ambulatory BP monitoring (ABPM) are out-of-office alternatives, and ABPM is considered the reference standard for BP assessment. Objective: To systematically review the accuracy of oscillometric office and home BP measurement methods for correctly classifying adults as having hypertension, defined using ABPM. Data Sources: PubMed, Cochrane Library, Embase, ClinicalTrials.gov, and DARE databases and the American Heart Association website (from inception to April 2021) were searched, along with reference lists from retrieved articles. Data Extraction and Synthesis: Two authors independently abstracted raw data and assessed methodological quality. A third author resolved disputes as needed. Main Outcomes and Measures: Random effects summary sensitivity, specificity, and likelihood ratios (LRs) were calculated for BP measurement methods for the diagnosis of hypertension. ABPM (24-hour mean BP ≥130/80 mm Hg or mean BP while awake ≥135/85 mm Hg) was considered the reference standard. Results: A total of 12 cross-sectional studies (n = 6877) that compared conventional oscillometric office BP measurements to mean BP during 24-hour ABPM and 6 studies (n = 2049) that compared mean BP on HBPM to mean BP during 24-hour ABPM were included (range, 117-2209 participants per analysis); 2 of these studies (n = 3040) used consecutive samples. The overall prevalence of hypertension identified by 24-hour ABPM was 49% (95% CI, 39%-60%) in the pooled studies that evaluated office measures and 54% (95% CI, 39%-69%) in studies that evaluated HBPM. All included studies assessed sensitivity and specificity at the office BP threshold of 140/90 mm Hg and the home BP threshold of 135/85 mm Hg. Conventional office oscillometric measurement (1-5 measurements in a single visit with BP ≥140/90 mm Hg) had a sensitivity of 51% (95% CI, 36%-67%), specificity of 88% (95% CI, 80%-96%), positive LR of 4.2 (95% CI, 2.5-6.0), and negative LR of 0.56 (95% CI, 0.42-0.69). Mean BP with HBPM (with BP ≥135/85 mm Hg) had a sensitivity of 75% (95% CI, 65%-86%), specificity of 76% (95% CI, 65%-86%), positive LR of 3.1 (95% CI, 2.2-4.0), and negative LR of 0.33 (95% CI, 0.20-0.47). Two studies (1 with a consecutive sample) that compared unattended automated mean office BP (with BP ≥135/85 mm Hg) with 24-hour ABPM had sensitivity ranging from 48% to 51% and specificity ranging from 80% to 91%. One study that compared attended automated mean office BP (with BP ≥140/90 mm Hg) with 24-hour ABPM had a sensitivity of 87.6% (95% CI, 83%-92%) and specificity of 24.1% (95% CI, 16%-32%). Conclusions and Relevance: Office measurements of BP may not be accurate enough to rule in or rule out hypertension; HBPM may be helpful to confirm a diagnosis. When there is uncertainty around threshold values or when office and HBPM are not in agreement, 24-hour ABPM should be considered to establish the diagnosis. © 2021 American Medical Association. All rights reserved