Postural hypotension

Facilitating ambulatory heart rate variability analysis using accelerometry-based classifications of body position and self-reported sleep

Objective.This study aimed to examine differences in heart rate variability (HRV) across accelerometer-derived position, self-reported sleep, and different summary measures (sleep, 24 h HRV) in free-living settings using open-source methodology.Approach.HRV is a biomarker of autonomic activity. As it is strongly affected by factors such as physical behaviour, stress, and sleep, ambulatory HRV analysis is challenging. Beat-to-beat heart rate (HR) and accelerometry data were collected using single-lead electrocardiography and trunk- and thigh-worn accelerometers among 160 adults participating in the SCREENS trial. HR files were processed and analysed in the RHRV R package. Start time and duration spent in physical behaviours were extracted, and time and frequency analysis for each episode was performed. Differences in HRV estimates across activities were compared using linear mixed models adjusted for age and sex with subject ID as random effect. Next, repeated-measures Bland-Altman analysis was used to compare 24 h RMSSD estimates to HRV during self-reported sleep. Sensitivity analyses evaluated the accuracy of the methodology, and the approach of employing accelerometer-determined episodes to examine activity-independent HRV was described.Main results.HRV was estimated for 31 289 episodes in 160 individuals (53.1% female) at a mean age of 41.4 years. Significant differences in HR and most markers of HRV were found across positions [Mean differences RMSSD: Sitting (Reference) - Standing (-2.63 ms) or Lying (4.53 ms)]. Moreover, ambulatory HRV differed significantly across sleep status, and poor agreement between 24 h estimates compared to sleep HRV was detected. Sensitivity analyses confirmed that removing the first and last 30 s of accelerometry-determined HR episodes was an accurate strategy to account for orthostatic effects.Significance.Ambulatory HRV differed significantly across accelerometry-assigned positions and sleep. The proposed approach for free-living HRV analysis may be an effective strategy to remove confounding by physical activity when the aim is to monitor general autonomic stress.

Determinants of fatigue in emergency department clinicians who wear personal protective equipment

OBJECTIVE

To determine the independent predictors for clinician fatigue and decline in cognitive function following a shift in the ED during early stages of the COVID-19 pandemic.

METHODS

This was a prospective, quasi-experimental study conducted in a metropolitan adult tertiary-referral hospital ED over 20 weeks in 2021. The participants were ED doctors and nurses working clinical shifts in an ED isolation area or high-risk zone (HRZ) with stringent personal protective equipment (PPE). The participants' objective and subjective fatigue was measured by the Samn-Perelli fatigue score and a psychomotor vigilance 'smart game' score, respectively. Postural signs/symptoms and urine specific gravity (SG) were measured as markers of dehydration.

RESULTS

Sixty-three participants provided data for 263 shifts. Median (interquartile range) age was 33 (28-38) years, 73% were female. Worsening fatigue score was associated with working afternoon shifts (afternoon vs day, adjusted odds ratio [aOR] 5.16 [95% confidence interval (CI) 1.32-20.02]) and in non-HRZ locations (HRZ vs non-HRZ, aOR 0.23 [95% CI 0.06-0.87]). Worsening cognitive function (game score) was associated with new onset postural symptoms (new vs no symptoms, aOR 4.14 [95% CI 1.34-12.51]) and afternoon shifts (afternoon vs day, aOR 3.13 [95% CI 1.16-8.44]). Working in the HRZ was not associated with declining cognitive function. Thirty-four (37%) of the 92 participants had an end of shift urine SG >1.030.

CONCLUSION

Working afternoon shifts was associated with fatigue. There was no association between HRZ allocation and fatigue, but our study was limited by a low COVID workload and fluctuating PPE requirements in the non-HRZs. Workplace interventions that target the prevention of fatigue in ED clinicians working afternoon shifts should be prioritised.

Drug-induced orthostatic hypotension: Cluster analysis of co-prescription patterns in older people in UK primary care

PURPOSE

Over 250 medications are reported to cause orthostatic hypotension, associated with serious adverse outcomes in older adults. Studies suggest a harmful cumulative risk of orthostatic hypotension with multiple medication use. However, there is limited evidence on the potential for harm in practice, particularly which drugs is co-prescribed and may increase risk of orthostatic hypotension.

METHODS

Retrospective cohort study and cluster analysis using general practice data from IQVIA Medical Research Data (IMRD) in patients aged ≥50 contributing data between 1 January 2018 and 31 December 2018. Thirteen drug groups known to be associated with orthostatic hypotension by mechanism, were analyzed and clusters generated by sex and age-band.

RESULTS

A total of 602 713 individuals aged ≥50 with 283 912 (47%) men and 318 801 (53%) women were included. The most prevalent prescriptions that might contribute to orthostatic hypotension were ACE inhibitors, calcium-channel blockers, beta-blockers, selective serotonin reuptake inhibitors and uroselective alpha-blockers. We identified distinct clusters of cardiovascular system (cardiovascular system) drugs in men and women at all ages. cardiovascular system plus psychoactive drug clusters were common in women at all ages, and in men aged ≤70. cardiovascular system plus uroselective alpha-blockers were identified in men aged ≥70.

CONCLUSIONS

Distinct clusters of drugs associated with orthostatic hypotension exist in practice, which change over the life course. Our findings highlight potentially harmful drug combinations that may cause cumulative risk of orthostatic hypotension in older people. This may guide clinicians about the potential of synergistic harm and to monitor for orthostatic hypotension if using combinations of cardiovascular system drugs, cardiovascular system plus psychoactive drugs and/or alpha-blockers-particularly in patients aged ≥70 or at high-risk due to comorbidity. Future research should consider quantifying the risk of drug-induced orthostatic hypotension with such drug combinations.

Incidence of postural hypotension recorded in UK general practice: an electronic health records study

BACKGROUND

Postural hypotension is a common condition associated with adverse outcomes in older adults. General practice plays an important role in identification of the condition.

AIM

To examine the incidence of postural hypotension between 2008 and 2018 in general practice and how trends vary by age, sex, year, and social deprivation.

DESIGN AND SETTING

Retrospective cohort study using electronic health records from the IQVIA Medical Research Data (IMRD) between 2008 and 2018.

METHOD

Patients were included if they were aged ≥50 years. Incident postural hypotension was identified as a new (first) recording of a postural hypotension code. Recording of incident postural hypotension was estimated per 10 000 person-years at risk (PYAR) according to age, sex, year, and social deprivation. Incident rate ratios were estimated by multivariable Poisson regression.

RESULTS

Of 2 911 260 patients, 24 973 had an electronic record indicating a new diagnosis of postural hypotension between 2008 and 2018. This was equivalent to 17.9 cases per 10 000 PYAR in males (95% confidence interval [CI] = 17.6 to 18.2) and 16.2 cases per 10 000 PYAR in females (95% CI = 15.9 to 16.5). A significant age-sex interaction was identified. Recorded postural hypotension rate increased with age and social deprivation, and reduced between 2008 and 2018. The rate was higher in males compared with females, particularly in older age groups (>80 years).

CONCLUSION

To the authors' knowledge, this is the first study to quantify incident recorded postural hypotension in general practice. The rate is lower than expected compared with studies in screened older populations. Potential barriers to identification include underreporting, underdetection owing to lack of time and/or poorly standardised methods of measurement, and poor coding. Future research should investigate current practice and approaches for increased detection such as education, practical methods of screening, and standardised measurement of postural blood pressure.

Orthostatic Hypotension in Hypertensive Adults: Harry Goldblatt Award for Early Career Investigators 2021

Orthostatic hypotension affects roughly 10% of individuals with hypertension and is associated with several adverse health outcomes, including dementia, cardiovascular disease, stroke, and death. Among adults with hypertension, orthostatic hypotension has also been shown to predict patterns of blood pressure dysregulation that may not be appreciated in the office setting, including nocturnal nondipping. Individuals with uncontrolled hypertension are at particular risk of orthostatic hypotension and may meet diagnostic criteria for the condition with a smaller relative reduction in blood pressure compared with normotensive individuals. Antihypertensive medications are commonly de-prescribed to address orthostatic hypotension; however, this approach may worsen supine or seated hypertension, which may be an important driver of adverse events in this population. There is significant variability between guidelines for the diagnosis of orthostatic hypotension with regards to timing and position of blood pressure measurements. Clinically relevant orthostatic hypotension may be missed when standing measurements are delayed or when taken after a seated rather than supine position. The treatment of orthostatic hypotension in patients with hypertension poses a significant management challenge for clinicians; however, recent evidence suggests that intensive blood pressure control may reduce the risk of orthostatic hypotension. A detailed characterization of blood pressure variability is essential to tailoring a treatment plan and can be accomplished using both in-office and out-of-office monitoring.