Dr. Ron’s Research Review – April 15, 2020

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This week’s research review focuses on white coat hypertension.

White-coat response is defined as higher blood pressure at the doctor’s office than in an ambulatory setting. It is observed in both ambulatory normotensive patients (white-coat hypertension) and in sustained hypertension (usually called white-coat phenomenon or white-coat effect).
Twenty-four hour ambulatory blood pressure monitoring (ABPM) is currently the diagnostic test of choice for its detection.
A clinic-based automated office blood pressure (AOBP) and home blood pressure measurement (HBPM) program detected white-coat BP elevation in one third of enrolled patients. (Doane et al., 2018)

The Deep-Breath Test

After taking two readings before the test (basal readings), the deep-breath maneuver was done by asking the patient to breath deeply for 30 seconds. Blood pressure is recorded immediately after the test, and then after 2 minutes.
Deep-breath test could be a useful office test to rule in white-coat effect in hypertensive patients. If systolic blood pressure drop is 20 mm Hg or more, the post-test odds of disease almost quadruples; if the drop is 25 mm Hg or more, the odds increase by a factor of 8. (Augustovski et al., 2004)

Parathyroid Hormone Vitamin D

A study examined serum parathyroid hormone (PTH)and vitamin D levels in white-coat (WCHT) and sustained hypertension (SHT) patients who had not been on antihypertensive treatment. We also investigated the association between serum PTH and vitamin D levels with respect to blood pressure in SHT and WCHT patients.
The study included 52 SHT patients (54.06 ± 9.2 years, 32 newly diagnosed and 20 previously diagnosed with SHT who had not been treated with antihypertensive medication for 3 months or more), 48 WCHT patients (53.64 ± 9.5 years), and 50 normotensive (NT) healthy controls (53.44 ± 8.4 years) in our study. In addition to routine tests, PTH and vitamin D levels were measured.
Serum PTH levels were significantly higher in SHT patients not taking antihypertensive medications than in WCHT patients and NT controls (p = 0.004). Although PTH levels were higher in WCHT than in NT groups, the difference was not statistically significant. In SHT patients, PTH levels showed a positive correlation with office systolic (r = 0.363, p = 0.008), office diastolic (r = 0.282, p = 0.038), home systolic (r = 0.390, p = 0.004), and home diastolic blood pressures (r = 0.397, p = 0.003). Serum vitamin D levels were similar in SHT, WCHT and NT groups. Vitamin D levels were not associated with blood pressures in the entire study group. Furthermore, no significant relation was found between vitamin D and PTH levels in SHT and WCHT groups.
PTH levels are significantly higher in untreated SHT patients than WCHT patients and NT subjects. However, vitamin D levels are similar in SHT, WCHT and NT groups.
There is a significant association between PTH levels and blood pressures suggesting PTH has a role in increase of blood pressure in SHT. (Akgül et al., 2017)

Vitamin D

A study evaluated vitamin D levels in white coat hypertension (WCHT) and compared with sustained hypertension (SHT) and with normotension (NT).
 Fifty-three normotensive, 42 WCHT, and 59 SHT patients were recruited in this study. The participants were matched for age, sex, and BMI. The vitamin D levels were determined using the electrochemiluminescence immunoassay method.
Plasma vitamin D levels were significantly lower in SHT than in the WCHT and NT groups (26.4±4.9, 34.3±3.6, and 36±5 ng/ml, respectively), and were similar in the WCHT and NT groups. There was a negative correlation between vitamin D levels and blood pressure parameters such as clinic systolic blood pressure (SBP), clinic diastolic blood pressure (DBP), 24-h SBP, 24-h DBP, daytime SBP, daytime DBP, night-time SBP, and night-time DBP (r=-0.554, -0.419, -0.629, -0.427, -0.559, -0.534, -0.607, -0.462, respectively, and all P<0.001) in the entire study group. Clinic SBP (B±SE=-0.97±0.037, P=0.009) and 24-h SBP (B±SE=-0.138±0.055, P=0.013) were identified as predictors for vitamin D levels in the entire study group.
Sustained hypertensive patients have lower vitamin D levels than white coat hypertensive and normotensive individuals. White coat hypertensive patients without other cardiovascular risk factors have higher vitamin D levels than sustained hypertensive patients, suggesting that they have a lower cardiovascular risk. (Alpsoy et al., 2016)

 

Dr. Ron

 


Articles

 

Association of parathyroid hormone and vitamin D with untreated hypertension: Is it different in white-coat or sustained hypertension
            (Akgül et al., 2017) Download
BACKGROUND:  Previous reports about the relationship between a high parathyroid hormone (PTH) and low vitamin D levels with blood pressure in different hypertension groups are conflicting. OBJECTIVE:  We studied serum PTH and vitamin D levels in white-coat (WCHT) and sustained hypertension (SHT) patients who had not been on antihypertensive treatment. We also investigated the association between serum PTH and vitamin D levels with respect to blood pressure in SHT and WCHT patients. METHODS:  We included 52 SHT patients (54.06 ± 9.2 years, 32 newly diagnosed and 20 previously diagnosed with SHT who had not been treated with antihypertensive medication for 3 months or more), 48 WCHT patients (53.64 ± 9.5 years), and 50 normotensive (NT) healthy controls (53.44 ± 8.4 years) in our study. In addition to routine tests, PTH and vitamin D levels were measured. RESULTS:  Serum PTH levels were significantly higher in SHT patients not taking antihypertensive medications than in WCHT patients and NT controls (p = 0.004). Although PTH levels were higher in WCHT than in NT groups, the difference was not statistically significant. In SHT patients, PTH levels showed a positive correlation with office systolic (r = 0.363, p = 0.008), office diastolic (r = 0.282, p = 0.038), home systolic (r = 0.390, p = 0.004), and home diastolic blood pressures (r = 0.397, p = 0.003). Serum vitamin D levels were similar in SHT, WCHT and NT groups. Vitamin D levels were not associated with blood pressures in the entire study group. Furthermore, no significant relation was found between vitamin D and PTH levels in SHT and WCHT groups. CONCLUSION:  PTH levels are significantly higher in untreated SHT patients than WCHT patients and NT subjects. However, vitamin D levels are similar in SHT, WCHT and NT groups. There is a significant association between PTH levels and blood pressures suggesting PTH has a role in increase of blood pressure in SHT.

Vitamin D levels in white coat and sustained hypertension.
            (Alpsoy et al., 2016)  Download
OBJECTIVE:  The plasma levels of vitamin D in patients with white coat hypertension (WCHT) have not been studied previously. The aim of this study was to evaluate vitamin D levels in WCHT and compare with sustained hypertension (SHT) and with normotension (NT). PATIENTS AND METHODS:  Fifty-three normotensive, 42 WCHT, and 59 SHT patients were recruited in this study. The participants were matched for age, sex, and BMI. The vitamin D levels were determined using the electrochemiluminescence immunoassay method. RESULTS:  Plasma vitamin D levels were significantly lower in SHT than in the WCHT and NT groups (26.4±4.9, 34.3±3.6, and 36±5 ng/ml, respectively), and were similar in the WCHT and NT groups. There was a negative correlation between vitamin D levels and blood pressure parameters such as clinic systolic blood pressure (SBP), clinic diastolic blood pressure (DBP), 24-h SBP, 24-h DBP, daytime SBP, daytime DBP, night-time SBP, and night-time DBP (r=-0.554, -0.419, -0.629, -0.427, -0.559, -0.534, -0.607, -0.462, respectively, and all P<0.001) in the entire study group. Clinic SBP (B±SE=-0.97±0.037, P=0.009) and 24-h SBP (B±SE=-0.138±0.055, P=0.013) were identified as predictors for vitamin D levels in the entire study group. CONCLUSION:  Our data show that sustained hypertensive patients have lower vitamin D levels than white coat hypertensive and normotensive individuals. White coat hypertensive patients without other cardiovascular risk factors have higher vitamin D levels than sustained hypertensive patients, suggesting that they have a lower cardiovascular risk.

The deep-breath test as a diagnostic maneuver for white-coat effect in hypertensive patients.
            (Augustovski et al., 2004) Download
BACKGROUND:  The white-coat effect is a common phenomenon in hypertensive patients, and there is no current useful office test to detect it. METHODS:  This was a cross-sectional study. We evaluated the deep-breath maneuver at the office as a diagnostic test of the white-coat effect. Participants included 83 adult patients with uncontrolled office hypertension. We measured sensitivity, specificity, likelihood ratios of different cutoff points, area under receiver operating characteristic (ROC) curve, and 95% confidence intervals. The reference standard used was 24-hour ambulatory blood pressure monitoring. RESULTS:  We included 73 patients [mean age, 58.7 +/- 9.5 years (mean +/- SD); 55% women]. The prevalence of white-coat effect was 62%. Comparing patients with white-coat effect versus those without, the deep-breath test resulted in a mean systolic blood pressure decrease of 17.8 and 10.9 mm Hg (P <.001) and a mean diastolic decrease of 6.6 and 5.4 mm Hg, respectively (P = not significant). The area under the ROC curve of systolic blood pressure change was 0.69 (95% confidence interval, 0.57 to 0.81). Interobserver agreement was very good. CONCLUSIONS:  The deep-breath test can be a helpful maneuver for the detection of white-coat effect. It has no major adverse effects and it may help avoid overtreatment and unnecessary further testing procedures.


 

Measuring and Managing Blood Pressure in a Primary Care Setting: A Pragmatic Implementation Study.
            (Doane et al., 2018) Download
BACKGROUND:  Accurate blood pressure (BP) measurement is essential to hypertension diagnosis and management. Automated office blood pressure (AOBP) and home blood pressure measurement (HBPM) may improve assessment, but barriers exist in primary care settings. METHODS:  We implemented an AOBP/HBPM program in a primary care clinic in 2015 to 2016. Patients with elevated BP determined by guideline-quality observed BP measurement and/or AOBP entered the HBPM program. Patients with average home BP ≥ 135/85 mm Hg provided HBPM results for medication adjustment. Clinic staff and patients completed satisfaction questionnaires. RESULTS:  Initial HBPM results in 183 patients with elevated office BP revealed white-coat BP elevation in 35% of untreated patients and in 37% of treated patients. The prevalence of white-coat BP elevation was similar whether enrollment BP was by observed BP or AOBP. Subsequent HBPM facilitated BP control in 49% of patients with elevated home BP. Most providers, staff, and patients endorsed the utility of the program. Barriers to implementation included a temporary period of incorrect AOBP technique, patients failing to provide HBPM results, and incorrect HBPM technique. DISCUSSION:  Our clinic-based AOBP/HBPM program detected white-coat BP elevation in one third of enrolled patients, facilitated control of home BP, and was acceptable to staff and patients. We identified barriers to be addressed to ensure sustainability.

 

References

Akgül, F, et al. (2017), ‘Association of parathyroid hormone and vitamin D with untreated hypertension: Is it different in white-coat or sustained hypertension’, PLoS One, 12 (11), e0188669. PubMed: 29176783
Alpsoy, S, et al. (2016), ‘Vitamin D levels in white coat and sustained hypertension.’, Blood Press Monit, 21 (3), 131-35. PubMed: 26735704
Augustovski, FA, et al. (2004), ‘The deep-breath test as a diagnostic maneuver for white-coat effect in hypertensive patients.’, J Am Board Fam Pract, 17 (3), 184-89. PubMed: 15226282
Doane, J, et al. (2018), ‘Measuring and Managing Blood Pressure in a Primary Care Setting: A Pragmatic Implementation Study.’, J Am Board Fam Med, 31 (3), 375-88. PubMed: 29743221