Muscle and skin sympathetic nerve traffic during physician and nurse blood pressure measurement

Blood pressure responses to testosterone therapy are amplified by hematocrit levels in opioid-induced androgen deficiency: a double-blind, randomized, placebo-controlled trial

Our study aimed to examine the effect of testosterone replacement therapy (TRT) on blood pressure in opioid-treated men with relative hypogonadism, and whether the effect of TRT on blood pressure was modified by body composition, red blood cell levels, or carotid intima media thickness. Men (over 18 years old) receiving opioid treatment and total testosterone less than 12 nmol were randomly assigned to receive either TRT or placebo. Baseline and 6-month measurements included anthropometric measurements, office blood pressure (OBPM), 24-h ambulatory blood pressure, blood samples, and carotid ultrasound. The mean systolic OBPM increased by 6.2 mmHg (0.2-12.1) in the TRT group and decreased by 7.0 mmHg (1.0-15.1) in the placebo group, with a mean difference of 13.2 mmHg (3.4-23.1), P  = 0.01. In the TRT group, a 10 mmHg increase in systolic OBPM was associated with an increase in hematocrit of 0.3% points (0.1-0.5) ( P  = 0.01), whereas no association was observed in the placebo group ( P  = 0.266). Daytime SBP showed a nonsignificant increase of 5.2 mmHg (-1.7, 12.1) ( P  = 0.134) in the TRT group compared to that in the placebo group. However, the impact of TRT on the increase in daytime ambulatory blood pressure was significantly accentuated by baseline values of BMI, hematocrit, and hemoglobin. In conclusion, TRT was associated with higher OBPM compared to placebo, and the increase in blood pressure was linked to higher hematocrit during TRT. Our data suggest that men with opioid-induced androgen deficiency, particularly those with obesity or red blood cell levels in the upper normal range, are more susceptible to increased daytime SBP during TRT.

Sympathetic Neural Mechanisms in Hypertension: Recent Insights

PURPOSE OF REVIEW

To examine published and unpublished data documenting the role of sympathetic neural factors in the pathogenesis of different hypertensive phenotypes. These phenotypes relate to attended or unattended blood pressure measurements, to nighttime blood pressure profile alterations, and to resistant, pseudoresistant, and refractory hypertension. Results of original clinical studies as well as of recent meta-analyses based on the behavior of different sympathetic biomarkers in various hypertensive forms will be also discussed.

RECENT FINDINGS

Studies performed in the past decade have shown that office blood pressure measurements, including in recent years those characterizing unattended or attended blood pressure assessment, are associated with profound changes in the behavior of different sympathetic biomarkers. This is the case for the clinical hypertensive phenotypes characterized by alterations in the nocturnal blood pressure profile and by sleep duration abnormalities. This is also the case for the clinical conditions defined as resistant, refractory, and pseudoresistant hypertension. Data reviewed in the present paper highlight the relevance of sympathetic neural factors in the development and progression of different clinical hypertensive phenotypes. This suggests that a common hallmark of the majority of the essential hypertensive states detectable in current clinical practice is represented by the alteration in the sympathetic blood pressure control.

Skin sympathetic nerve activity and nocturnal blood pressure nondipping in patients with postural orthostatic tachycardia syndrome

OBJECTIVE

Postural orthostatic tachycardia syndrome (POTS) is associated with abnormal blood pressure (BP) regulation and increased prevalence of nocturnal nondipping. We hypothesized that nocturnal nondipping of BP is associated with elevated skin sympathetic nerve activity (SKNA) in POTS.

METHOD

We used an ambulatory monitor to record SKNA and electrocardiogram from 79 participants with POTS (36 ± 11 years, 72 women), including 67 with simultaneous 24-h ambulatory BP monitoring.

RESULTS

Nocturnal nondipping of BP was present in 19 of 67 (28%) participants. The nondipping group had a higher average SKNA (aSKNA) from midnight of day 1 to 0100 h on day 2 than the dipping group ( P  = 0.016, P  = 0.030, respectively). The differences (Δ) of aSKNA and mean BP between daytime and night-time were more significant in the dipping group compared with the nondipping group (ΔaSKNA 0.160 ± 0.103 vs. 0.095 ± 0.099 μV, P  = 0.021, and Δmean BP 15.0 ± 5.2 vs. 4.9 ± 4.2 mmHg, P  < 0.001, respectively). There were positive correlations between ΔaSKNA and standing norepinephrine (NE) (r = 0.421, P  = 0.013) and the differences between standing and supine NE levels ( r  = 0.411, P  = 0.016). There were 53 (79%) patients with SBP less than 90 mmHg and 61 patients (91%) with DBP less than 60 mmHg. These hypotensive episodes were associated with aSKNA of 0.936 ± 0.081 and 0.936 ± 0.080 μV, respectively, which were both significantly lower than the nonhypotensive aSKNA (1.034 ± 0.087 μV, P  < 0.001 for both) in the same patient.

CONCLUSION

POTS patients with nocturnal nondipping have elevated nocturnal sympathetic tone and blunted reduction of SKNA between day and night. Hypotensive episodes were associated with reduced aSKNA.

The many faces of hypertension in individuals with type 1 diabetes

Several disturbed blood pressure (BP) patterns, including disparities between office and out-of-office BP measurements (such as white-coat and masked hypertension), disturbed circadian BP variability (such as abnormal dipping patterns and nocturnal hypertension) and treatment-resistant hypertension, are common in individuals with type 1 diabetes. Consequently, office or home BP measurements alone may not reflect real BP variation and may lead to inadequate diagnosis and treatment of hypertension. The early detection of these disturbed BP patterns is especially crucial in individuals with type 1 diabetes, as these patterns may indicate future development of adverse cardiovascular and renal outcomes. In this review we will describe these disturbed BP patterns and discuss recent findings on their prevalence and outcomes. We will also address critical areas for future research to determine the true prevalence and prognosis of disturbed BP patterns, and to optimize and improve the knowledge and management of high-risk individuals with type 1 diabetes and disturbed BP patterns.

Relations between white coat effect of blood pressure and arterial stiffness

The aim of this study was to analyze the relationship between brachial-ankle pulse wave velocity (b-a PWV) and white coat effect (WCE), that is the difference between the elevated office blood pressure (BP) and the lower mean daytime pressure of ambulatory BP, in a mixed population of normotention, untreated sustained hypertension, sustained controlled hypertension, sustained uncontrolled hypertension, white coat hypertension, white coat uncontrolled hypertension. A total of 444 patients with WCE for systolic BP (54.1% female, age 61.86 ± 13.3 years) were enrolled in the study. Patients were separated into low WCE (<9.5 mm Hg) and high WCE (≥9.5 mm Hg) according to the median of WCE. The subjects with a high WCE showed a greater degree of arterial stiffness than those with a low WCE for systolic BP values (P < .05). The b-a PWV were 17.2 ± 3.3 m/s and 18.4 ± 3.4 m/s in low WCE and high WCE, respectively. The b-a PWV increased with the increase of WCE, showing a positive correlation between them (P > .05 for non-linearity). The significant association between the high WCE and the b-a PWV was confirmed by the results of multiple regression analysis after adjusting for confounding factors (β = .78, 95% Cl .25-1.31, P = . 004). Similar results were observed in subgroups. In conclusion, WCE is significantly associated with arterial stiffness. More research is needed to determine the WCE and target organ damage.

Comparison of nurse attended and unattended automated office blood pressure with conventional measurement techniques in clinical practice

Accuracy in blood pressure measurement is critical for proper hypertension diagnosis and treatment in clinical practice. Automated office blood pressure (AOBP) can simplify the measurement process, reducing human error and minimizing the white-coat effect in the unattended mode. The aim of this study was to compare AOBP, both unattended and nurse attended, with conventional office and out-of-office blood pressure measurement techniques. Four different methods of blood pressure measurement were performed in a cohort of hypertensive patients: conventional office blood pressure (OBP), unattended automated office blood pressure (uAOBP), nurse attended automated office blood pressure (nAOBP), and home blood pressure monitoring (HBPM). uAOBP and nAOBP were conducted with the same rigorous standardized procedure. We enrolled 118 consecutive patients. nAOBP values were slightly higher than uAOBP ones (respectively 132.8/73.3 ± 19.4/12.9 and 129.2/71.1 ± 19.0/12.3 mmHg), even if the difference was influenced by order of execution of AOBP measurement. nAOBP was significantly lower than HBPM and OBP (mean values 135.2/80.9 ± 16.6/8.1 and 140.9/84.6 ± 18.7/10.8 mmHg, respectively). AOBP, either attended or unattended, provides lower values than conventional OBP. uAOBP and nAOBP values showed small differences, even if they are not completely interchangeable. This evidence reflects a lower white-coat effect, even in nurse attended technique, but is also due to a lower measurement error through the application of a rigorous standardized protocol.

Skin Sympathetic Nerve Activity and Ventricular Arrhythmias in Acute Coronary Syndrome

BACKGROUND

Acute coronary syndrome (ACS) is major cause of ventricular arrhythmias (VA) and sudden death. neuECG is a non-invasive method to simultaneously measure skin sympathetic nerve activity (SKNA) and electrocardiogram (ECG).

OBJECTIVE

To test the hypotheses that (1) ACS increases the average SKNA (aSKNA), (2) the magnitude of aSKNA elevation is associated with VA during ACS and (3) there is a gender difference of aSKNA in patients without and with ACS.

METHODS

We prospectively studied 128 ACS and 165 control participants. The neuECG was recorded with electrocardiogram (ECG) Lead I configuration at baseline, during mental math stress and during recovery (5-min each). All recordings were done in the morning.

RESULTS

In control group, women have higher aSKNA (μV) than men at baseline (0.82±0.25 vs 0.73±0.20, p=0.009) but not during mental stress (1.21±0.36 vs 1.16±0.36, p=0.394), suggesting women had lower sympathetic reserve. In comparison, ACS is associated with equally elevated aSKNA (μV) in women vs men at baseline (1.14±0.33 vs 1.04±0.35, p=0.531), during mental stress (1.46±0.32 vs 1.33 ±0.37, p=0.113) and during recovery (1.30±0.33 1.11±0.30, p=0.075). After adjusting for age and gender, the adjusted odds ratio for VA including ventricular tachycardia and fibrillation is 1.23 (95% confidence interval 1.05-1.44) for each 0.1 μV elevation of aSKNA. The aSKNA is positively correlated with plasma norepinephrine level.

CONCLUSIONS

ACS is associated with elevated aSKNA and the magnitude of aSKNA elevation is associated with occurrences of VA. Women have higher aSKNA and lower SKNA reserve than men in control but not in ACS patients.

Acute Effects of Electronic and Tobacco Cigarette Smoking on Sympathetic Nerve Activity and Blood Pressure in Humans

Acute tobacco cigarette (TC) smoking increases blood pressure and sympathetic nerve activity, whereas there are scarce data on the impact of electronic cigarette (EC) smoking. We assessed the acute effects of TC, EC and sham smoking on blood pressure, heart rate and sympathetic nervous system. Methods: We studied 12 normotensive male habitual smokers (mean age 33 years) free of cardiovascular disease. The study design was randomized and sham controlled with three experimental sessions (sham smoking, TC smoking and EC smoking). After baseline measurements at rest, the subjects were then asked to smoke (puffing habits left uncontrolled) two TC cigarettes containing 1.1 mg nicotine, EC smoking or simulated smoking with a drinking straw with a filter (sham smoking), in line with previous methodology. Results: EC smoking at 5 and 30 min compared to baseline was accompanied by the augmentation of mean arterial pressure (MAP) and heart rate (p < 0.001 for all). The muscle sympathetic nerve activity (MSNA) decrease was significant during both TC and EC sessions (p < 0.001 for both comparisons) and was similar between them (−25.1% ± 9.8% vs. −34.4% ± 8.3%, respectively, p = 0.018). Both MSNA decreases were significantly higher (p < 0.001 for both comparisons) than that elicited by sham smoking (−4.4% ± 4.8%). Skin sympathetic nerve activity increase was significant in both TC and EC groups (p < 0.001 for both comparisons) and similar between them (73.4% ± 17.9% and 71.9% ± 7%, respectively, p = 0.829). Conclusions: The unfavorable responses of sympathetic and arterial pressure to EC smoking are similar to those elicited by TC in healthy habitual smokers.

Sympathetic Neural Mechanisms Underlying Attended and Unattended Blood Pressure Measurement

[Figure: see text].

Current View of Diagnosing Small Fiber Neuropathy

Small fiber neuropathy (SFN) is a disorder of the small myelinated Aδ-fibers and unmyelinated C-fibers [5, 6]. SFN might affect small sensory fibers, autonomic fibers or both, resulting in sensory changes, autonomic dysfunction or combined symptoms [7]. As a consequence, the symptoms are potentially numerous and have a large impact on quality of life [8]. Since diagnostic methods for SFN are numerous and its pathophysiology complex, this extensive review focusses on categorizing all aspects of SFN as disease and its diagnosis. In this review, sensitivity in combination with specificity of different diagnostic methods are described using the areas under the curve. In the end, a diagnostic work-flow is suggested based on different phenotypes of SFN.

Skin sympathetic nerve activity in patients with obstructive sleep apnea

BACKGROUND

Obstructive sleep apnea (OSA) is associated with increased cardiac arrhythmia and sudden cardiac death. We recently developed a new method (neuECG) to noninvasively measure electrocardiogram and skin sympathetic nerve activity (SKNA).

OBJECTIVE

The purpose of this study was to test the hypothesis that SKNA measured during sleep study is higher in patients with OSA than in those without OSA.

METHODS

We prospectively recorded neuECG and polysomnography in 26 patients undergoing a sleep study. Sleep stages were scored into rapid eye movement (REM), and non-REM sleep stages 1 (N1), 2 (N2), and 3 (N3). Average voltage of skin sympathetic nerve activity (aSKNA) and SKNA burst area were calculated for quantification. Apnea/hypopnea index (AHI) >5 per hour was used to diagnose OSA.

RESULTS

There was a positive correlation (r = 0.549; P = .018) between SKNA burst area and the arousal index in OSA but not in the control group. aSKNA during sleep was 0.61 ± 0.09 μV in OSA patients (n = 18) and 0.53 ± 0.04 μV in control patients (n = 8; P = .025). Burst area was 3.26 (1.90-4.47) μV·s/min in OSA patients and 1.31 (0.67-1.94) μV·s/min in control (P = .047). More apparent differences were found during N2, when the burst area in OSA (3.06 [1.46-5.52] μV·s/min) was much higher than that of the control (0.89 [0.79-1.65] μV·s/min; P = .03).

CONCLUSION

OSA patients have higher SKNA activity than control patients, with the most pronounced differences observed during N2. Arousal at the end of apnea episodes is associated with large SKNA bursts. Overlaps of aSKNA and SKNA burst area between groups suggest that not all OSA patients have increased sympathetic tone.

Comparison of self- and nurse-measured office blood pressure in patients with chronic kidney disease

OBJECTIVE

As blood pressure (BP) control is very important in chronic kidney disease (CKD), we investigated how office BP is influenced by the measurement circumstances and compared nonautomated self- and nurse-measured BP values.

MATERIALS AND METHODS

Two hundred stage 1-5 CKD patients with scheduled visits to an outpatient clinic were randomized to either self-measured office BP (SMOBP) followed by nurse-measured office BP (NMOBP) or NMOBP followed by SMOBP. The participants had been educated to perform the self-measurement in at least one previous visit. The SMOBP and NMOBP measurement series both consisted of three recordings, and the means of the last two recordings during SMOBP and NMOBP were compared for the 174 (mean age 52.5 years) with complete BP data.

RESULTS

SMOBP and NMOBP showed similar systolic (135.3 ± 16.6 vs 136.4 ± 17.4 mmHg, Δ = 1.1 mmHg, P = 0.13) and diastolic (81.5 ± 10.2 vs 82.2 ± 10.4 mmHg, Δ = 0.6 mmHg, P = 0.09) values. The change in BP from the first to the third recording was not different for SMOBP and NMOBP. In 17 patients, systolic SMOBP was ≥10 mmHg higher than NMOBP and in 28 patients systolic NMOBP exceeded SMOBP by ≥10 mmHg. The difference between systolic SMOBP and NMOBP was independent of CKD stage and the number of medications, but significantly more pronounced in patients above 60 years.

CONCLUSION

In a population of CKD patients, there is no clinically relevant difference in SMOBP and NMOBP when recorded at the same visit. However, in 25% of the patients, systolic BP differs ≥10 mmHg between the two measurement modalities.

Current status of white coat hypertension: where are we?

White coat hypertension (WCH) is characterised by an elevated clinic blood pressure (BP) with normal ambulatory or home BP. It is well recognised in clinical practice and occurs in approximately one-third of untreated patients with elevated clinic BP. Current evidence suggests that WCH is associated with cardiovascular risk factors, including the development of sustained hypertension and the presence of target organ damage. However, its effects on cardiovascular outcomes remain a matter of debate. There is also insufficient evidence from randomised controlled trials to determine whether WCH warrants treatment. This narrative review aims to provide an update on the current understanding of WCH. It focuses on the clinical characteristics and potential implications of WCH, its relationship to cardiovascular risk and the evidence regarding treatment. Gaps in existing research are also highlighted.

Skin sympathetic nerve activity and ventricular rate control during atrial fibrillation

BACKGROUND

The relationship between the ventricular rate (VR) during atrial fibrillation (AF) and skin sympathetic nerve activity (SKNA) remains unclear.

OBJECTIVE

The purpose of this study was to test the hypothesis that SKNA bursts accelerate VR during AF.

METHODS

We simultaneously recorded electrocardiogram and SKNA in 8 patients (median age 66.0 years [interquartile range {IQR} 59.0-77.0 years]; 4 men [50%]) with 30 paroxysmal AF episodes (all >10-minute long) and 12 patients (73.0 years [IQR 60.5-80.0 years]; 6 men [50%]) with persistent AF. The average amplitude of SKNA (aSKNA [μV]) during AF was analyzed in 1-minute windows and binned, showing 2 Gaussian distributions. We used the mean + 3SD of the first Gaussian distribution as the threshold that separates burst from baseline (nonburst) SKNA. All 1-minute aSKNA values above the threshold were detected, and the area between aSKNA and baseline of every 1 minute was calculated and added as burst area.

RESULTS

VR was higher during SKNA bursts than during the nonburst period (103 beats/min [IQR 83-113 beats/min] vs 88 beats/min [IQR 76-101 beats/min], respectively; P = .003). In the highest quartile of the burst area during persistent AF, the scatterplot of maximal aSKNA and VR during each SKNA burst shows higher aSKNA and VR. The overall estimate of the correlation between maximal VR and aSKNA during bursts show a positive correlation in the highest quartile of the burst area (0.64; 95% confidence interval 0.54-0.74; P < .0001).

CONCLUSION

SKNA bursts are associated with VR acceleration. These SKNA bursts may be new therapeutic targets for rate control during AF.

Effects of anesthetic and sedative agents on sympathetic nerve activity

BACKGROUND

The effects of sedative and anesthetic agents on sympathetic nerve activity (SNA) are poorly understood.

OBJECTIVE

The purpose of this study was to determine the effects of commonly used sedative and anesthetic agents on SNA in ambulatory dogs and humans.

METHODS

We implanted radiotransmitters in 6 dogs to record stellate ganglion nerve activity (SGNA), subcutaneous nerve activity (ScNA), and blood pressure (BP). After recovery, we injected dexmedetomidine (3 μg/kg), morphine (0.1 mg/kg), hydromorphone (0.05 mg/kg), and midazolam (0.1 mg/kg) on different days. We also studied 12 human patients (10 male; age 68.0 ± 9.1 years old) undergoing cardioversion for atrial fibrillation with propofol (0.77 ± 0.18 mg/kg) or methohexital (0.65 mg/kg) anesthesia. Skin sympathetic nerve activity (SKNA) and electrocardiogram were recorded during the study.

RESULTS

SGNA and ScNA were significantly suppressed immediately after administration of dexmedetomidine (P = .000 and P = .000, respectively), morphine (P = .011 and P = .014, respectively), and hydromorphone (P = .000 and P = .012, respectively), along with decreased BP and heart rate (HR) (P <.001 for each). Midazolam had no significant effect on SGNA and ScNA (P = .248 and P = .149, respectively) but increased HR (P = .015) and decreased BP (P = .004) in ambulatory dogs. In patients undergoing cardioversion, bolus propofol administration significantly suppressed SKNA (from 1.11 ± 0.25 μV to 0.77 ± 0.15 μV; P = .001), and the effects lasted for at least 10 minutes after the final cardioversion shock. Methohexital decreased chest SKNA from 1.59 ± 0.45 μV to 1.22 ± 0.58 μV (P = .000) and arm SKNA from 0.76 ± 0.43 μV to 0.55 ± 0.07 μV (P = .001). The effects lasted for at least 10 minutes after the cardioversion shock.

CONCLUSION

Propofol, methohexital, dexmedetomidine, morphine, and hydromorphone suppressed, but midazolam had no significant effects on, SNA.

Target Organ Complications and Cardiovascular Events Associated With Masked Hypertension and White-Coat Hypertension: Analysis From the Dallas Heart Study

BACKGROUND

Multiple epidemiological studies from Europe and Asia have demonstrated increased cardiovascular risks associated with isolated elevation of home blood pressure (BP) or masked hypertension (MH). Previous studies have not addressed cardiovascular outcomes associated with MH and white-coat hypertension (WCH) in the general population in the United States.

OBJECTIVES

The goal of this study was to determine hypertensive target organ damage and adverse cardiovascular outcomes associated with WCH (high clinic BP, ≥140/90 mm Hg; normal home BP, <135/85 mm Hg), MH (high home BP, ≥135/85 mm Hg; normal clinic BP, <140/90 mm Hg), and sustained hypertension (high home and clinic BP) in the DHS (Dallas Heart Study), a large, multiethnic, probability-based population cohort.

METHODS

Associations among WCH, MH, sustained hypertension, and aortic pulsed wave velocity by magnetic resonance imaging; urinary albumin-to-creatinine ratio; and cystatin C were evaluated at study baseline. Then, associations between WCH and MH with incident cardiovascular outcomes (coronary heart disease, stroke, atrial fibrillation, heart failure, and cardiovascular death) over a median follow-up period of 9 years were assessed.

RESULTS

The study cohort comprised 3,027 subjects (50% African Americans). The sample-weighted prevalence rates of WCH and MH were 3.3% and 17.8%, respectively. Both WCH and MH were independently associated with increased aortic pulsed wave velocity, cystatin C, and urinary albumin-to-creatinine ratio. Both WCH (adjusted hazard ratio: 2.09; 95% confidence interval: 1.05 to 4.15) and MH (adjusted hazard ratio: 2.03; 95% confidence interval: 1.36 to 3.03) were independently associated with higher cardiovascular events compared with the normotensive group, even after adjustment for traditional cardiovascular risk factors.

CONCLUSIONS

In a multiethnic U.S. population, both WCH and MH were independently associated with increased aortic stiffness, renal injury, and incident cardiovascular events. Because MH is common and associated with an adverse cardiovascular profile, home BP monitoring should be routinely performed among U.S. adults.

Target organ complications and prognostic significance of alerting reaction: analysis from the Dallas Heart Study

OBJECTIVE

Noninvasive blood pressure (BP) measurement often triggers a transient rise in BP, known as an alerting reaction. However, the prevalence and prognostic significance of the alerting reaction has never been assessed in the general population.

METHODS

We evaluated the association between the alerting reaction and left ventricular mass by MRI and urinary albumin-to-creatinine ratio in the Dallas Heart Study, a large population sample of 3069 individuals. Participants were categorized into four groups based on levels of consecutive BP: first, normal first BP and average third to fifth (avg3-5) BP of less than 140/90 mmHg (control group); second, high first BP of at least 140/90 mmHg and normal (avg3-5) BP (alerting reaction group); third, normal first BP and high (avg3-5) BP; and fourth, high first to fifth BP. Then, associations between BP categories with incident cardiovascular outcomes (coronary heart disease, stroke, atrial fibrillation, heart failure, and cardiovascular death) over a median follow-up period of 9.4 years were assessed.

RESULTS

The sample-weighted prevalence of isolated hypertension during the first BP measurement was 9.6%. Presence of an alerting reaction was independently associated with increased left ventricular mass, urinary albumin-to-creatinine ratio, cardiovascular events after adjustment for traditional cardiovascular risk factors, and baseline BP (adjusted hazard ratio 1.24, 95% confidence interval 1.07-1.43).

CONCLUSION

Our study indicated that the alerting reaction is independently associated with increased cardiovascular and renal complications.

Doctors record higher blood pressures than nurses: systematic review and meta-analysis

BACKGROUND

The magnitude of the 'white coat effect', the alerting rise in blood pressure, is greater for doctors than nurses. This could bias interpretation of studies on nurse-led care in hypertension, and risks overestimating or overtreating high blood pressure by doctors in clinical practice.

AIM

To quantify differences between blood pressure measurements made by doctors and nurses.

DESIGN AND SETTING

Systematic review and meta-analysis using searches of MEDLINE, CENTRAL, CINAHL, Embase, journal collections, and conference abstracts.

METHOD

Studies in adults reporting mean blood pressures measured by doctors and nurses at the same visit were selected, and mean blood pressures extracted, by two reviewers. Study risk of bias was assessed using modified Cochrane criteria. Outcomes were pooled across studies using random effects meta-analysis.

RESULTS

In total, 15 studies (11 hypertensive; four mixed hypertensive and normotensive populations) were included from 1899 unique citations. Compared with doctors' measurements, nurse-measured blood pressures were lower (weighted mean differences: systolic -7.0 [95% confidence interval {CI} = -4.7 to -9.2] mmHg, diastolic -3.8 [95% CI = -2.2 to -5.4] mmHg). For studies at low risk of bias, differences were lower: systolic -4.6 (95% CI = -1.9 to -7.3) mmHg; diastolic -1.7 (95% CI = -0.1 to -3.2) mmHg. White coat hypertension was diagnosed more frequently based on doctors' than on nurses' readings: relative risk 1.6 (95% CI =1.2 to 2.1).

CONCLUSIONS

The white coat effect is smaller for blood pressure measurements made by nurses than by doctors. This systematic difference has implications for hypertension diagnosis and management. Caution is required in pooling data from studies using both nurse- and doctor-measured blood pressures.