Nighttime dipping status and risk of cardiovascular events in patients with untreated hypertension: A systematic review and meta-analysis.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of non-randomized cohort studies
PubMed 33164307 · doi:10.1111/jch.14039
What was done
A systematic review and meta-analysis of MEDLINE, Embase, Cochrane Library, and gray literature through March 2020 evaluated nocturnal blood pressure dipping patterns via ambulatory blood pressure monitoring (ABPM) in untreated hypertensive patients. Eligible studies were cohorts with follow-up exceeding 6 months. Study quality was evaluated using the Newcastle-Ottawa scale.
What was found
Seven cohort studies comprising 10,438 untreated hypertensive patients were analyzed. Dippers at baseline (n = 7,081) had lower risks of cardiovascular events (RR = 0.67, 95% CI: 0.49 to 0.92) and total mortality (RR = 0.71, 95% CI: 0.59 to 0.86) compared to non-dippers (n = 3,357). When divided into four dipping categories, only reverse dippers showed increased risk relative to dippers for cardiovascular events (RR = 0.47, 95% CI: 0.33 to 0.66 for dippers vs reverse dippers) and stroke (RR = 0.39, 95% CI: 0.22 to 0.72). Non-dipping alone (excluding reverse dipping) was not significantly associated with cardiovascular events (RR = 0.84, 95% CI: 0.61 to 1.16) or total mortality (RR = 0.78, 95% CI: 0.53 to 1.13).
Why it matters
Risk stratification in untreated hypertension is predominantly driven by reverse nocturnal dipping rather than general non-dipping. Distinguishing reverse dippers on ambulatory monitoring provides more accurate prognostic insight than broad non-dipping classifications.
Limits
Analysis relied on only seven observational cohort studies, introducing potential residual confounding. The abstract does not report medication initiation during follow-up, baseline comorbidity distributions, or variations in ABPM diagnostic thresholds across included cohorts.
Cited by
- supports People whose blood pressure does not dip during sleep ('non-dippers') have significantly higher cardiovascular, heart attack, and stroke risk.