Comparison of the actigraph versus patients' diary information in defining circadian time periods for analyzing ambulatory blood pressure monitoring data

Comparing effect of definition of diurnal periods by diary, fixed periods, and actigraphy on ambulatory blood pressure parameters in a Chinese population

BACKGROUND

Reliable measurement of daytime and night-time blood pressure (BP), and degree of BP dipping during sleep during ambulatory blood pressure monitoring (ABPM) requires an accurate definition of sleep time (diurnal definition). However, superiority of any diurnal definition on ABPM remains unclear. The present study compared mean daytime and night-time SBP and DBP using different methods for diurnal definition: patient's diary, wide-defined and narrow-defined fixed periods, and actigraphy, in a Chinese population with diagnosed essential hypertension. We hypothesize that BP values from actigraphy are different from BP obtained by other methods and associated with end-organ damage (i.e. impaired renal function, proteinuria, left ventricular hypertrophy).

METHODS

From April 2017 to October 2019, 203 Chinese patients diagnosed with hypertension were recruited prospectively from Lek Yuen Clinic and 179 completed a 48-h ABPM study, wearing a validated actigraph and completed a sleep diary. Presence of end-organ damage was retrieved from the computerized clinical management system. The differences in the mean BP values provided by different diurnal definition were compared using paired t tests and Bland-Altman plots. The prevalence of elevated BP, dipping status categories, overall percentage agreement and the Kappa statistic were calculated by pairwise comparisons between different diurnal definitions. The reproducibility was also estimated and logistic regression was used to examine the relationship between BP values from different diurnal definitions and end-organ damage.

RESULTS

Mean daytime and night-time BP values were similar regardless of the definition used (mean difference <2 mmHg). Kappa statistics and overall percentage agreement found excellent agreement between different definitions to diagnose elevated daytime BP (Kappa ranged from 0.80 to 0.91) and night-time BP (Kappa ranged from 0.74 to 0.89). Good agreement to diagnose nondipping was also detected (Kappa ranged from 0.65 to 0.78). Furthermore, ABPM values were most reproducible when diurnal periods were defined by patient's diary (intra-class correlation coefficient = 0.82-0.93). Daytime and night-time BP values obtained using different diurnal definitions did not differ in their association to end-organ damage.

CONCLUSION

Differing definitions of diurnal periods provide similar mean BP values among a Chinese hypertensive population and have good agreement for diagnosis of elevated BP and dipping status. In individual patients, clinicians should be aware that different definitions of diurnal periods can lead to a 3-5 mmHg difference in patient's BP values and may affect the diagnosis of elevated BP in patients with BP close to diagnostic thresholds. The current study supports using the patient's diary to define diurnal periods, which provided the best reproducibility.

Automatic data extraction from 24 hour blood pressure measurement reports of a large multicenter clinical trial

BACKGROUND AND OBJECTIVES

Ambulatory blood pressure monitoring (ABPM) is usually reported in descriptive values such as circadian averages and standard deviations. Making use of the original, individual blood pressure measurements may be advantageous, particularly for research purposes, as this increases the flexibility of the analytical process, enables alternative statistical analyses and provide novel insights. Here we describe the development of a new multistep, hierarchical data extraction algorithm to collect raw data from .pdf reports and text files as part of a large multi-center clinical study.

METHODS

Original reports were saved in a nested file system, from which they were automatically extracted, read and saved into databases with custom made programs written in Python 3. Data were further processed, cleaned and relevant descriptive statistics such as averages and standard deviations calculated according to a variety of definitions of day- and night-time. Additionally, data control mechanisms for manual review of the data and programmatic auto-detection of extraction errors was implemented as part of the project.

RESULTS

The developed algorithm extracted 97% of the data automatically, the missing data consisted mostly of reports that were saved incorrectly or not formatted in the specified way. Manual checks comparing samples of the extracted data to original reports indicated a high level of accuracy of the extracted data, no errors introduced due to flaws in the extraction software were detected in the extracted dataset.

CONCLUSIONS

The developed multistep, hierarchical data extraction algorithm facilitated collection from different file formats and paired with database cleaning and data processing steps led to an effective and accurate assembly of raw ABPM data for further and adjustable analyses. Manual work was minimized while data quality was ensured with standardized, reproducible procedures.

Defining the nocturnal period in 24-h ambulatory blood pressure monitoring: a comparison of three methods

OBJECTIVES

The purpose of our study was to compare three definitions of ambulatory blood pressure (BP) nocturnal period and to assess their agreement in determining nocturnal BP dipping patterns.

METHODS

We investigated 69 subjects with metabolic syndrome, aged 50-55 years. In all subjects, we assessed 24-h BP monitoring, electrocardiogram and actigraphy profiles. The nocturnal period was defined in three ways: as a fixed narrow nighttime period from 01:00 to 06:00, as a self-reported sleeping period and as a disappearance and onset of physical activity recorded by the actigraph.

RESULTS

Our study revealed a significant discrepancy between the self-reported and actigraphy-based nocturnal periods (P < 0.001). In addition, different definitions of the nighttime yielded significant differences in determining nondipping, extreme dipping and dipping BP patterns, the identification of the latter being affected the most. The actigraphy-based approach best aligned with the fixed-time determination of the nocturnal period: Cohen's kappa coefficient for the nondipping pattern was 0.78 (0.58-1), for the dipping pattern 0.75 (0.59-0.91) and for the extreme dipping pattern 0.81 (0.65-0.97). In comparison to the self-reported determination of the nocturnal period, using the actigraphy-based approach resulted in reclassifying the nocturnal BP pattern in 20.3% of subjects.

CONCLUSIONS

The lack of agreement between fixed-time, self-reported and actigraphy-based determinations of the nighttime period affects the identification of the nocturnal BP patterns. In comparison to the self-reported nocturnal period estimation, the actigraphy-based approach results in the reclassification of BP dipping status in every fifth subject.

Blood pressure monitoring in sleep: time to wake up

Hypertension is a highly common condition with well-established adverse consequences. Ambulatory blood pressure monitoring has repeatedly been shown to better predict cardiovascular outcomes and mortality, compared to single office visit blood pressure. Non-dipping of sleep-time blood pressure is an independent marker for increased cardiovascular risk. We review blood pressure variability and the challenges of blood pressure monitoring during sleep. Although pathological sleep such as obstructive sleep apnea has been associated with non-dipping of sleep-time blood pressure, blood pressure is not routinely measured during sleep due to lack of unobtrusive blood pressure monitoring technology. Second, we review existing noninvasive continuous blood pressure monitoring technologies. Lastly, we propose including sleep-time blood pressure monitoring during sleep studies and including sleep studies in patients undergoing ambulatory blood pressure monitoring.

Changes in Ambulatory Blood Pressure Phenotype over Time in Children and Adolescents with Elevated Blood Pressures

OBJECTIVE

To determine the stability of ambulatory blood pressure monitoring (ABPM) over time in children referred for evaluation of elevated BPs and assess for factors predicting change.

STUDY DESIGN

This retrospective chart review conducted at Seattle Children's Hospital and University of Pittsburgh Medical Center Children's Hospital of Pittsburgh identified 124 children referred for elevated BPs with 2 ABPM studies at least 6 months apart. All subjects received lifestyle counseling. Subjects with secondary hypertension (HTN) or on antihypertensive medication were excluded. ABPM phenotype was classified using American Heart Association guidelines as showing normal BP, prehypertension, and HTN. Generalized linear mixed effect regression models were used to regress stable, improving, or worsening HTN outcomes at study follow-up on baseline BP index and load variables.

RESULTS

The median age of patients was 14.1 years (73% males) and the median interval between studies was 18 months. ABPM phenotype changed in 58 of 124 children, with 16% worsening and 31% improving. Older age was associated with persistence of HTN. Although not significant, decrease in body mass index z-score tracked with sustained normal ambulatory BPs.

CONCLUSIONS

Although the sample size is small, our study suggests ABPM phenotype shows variability over time. Further study is required to identify factors supporting risk for progression of ABPM phenotype over time.

Sleep architecture measurement based on cardiorespiratory parameters

This paper presents a method for the detection of wakeful state, rapid eye movement sleep (REM), light sleep (N1&N2) and deep sleep (N3&N4) based on cardiorespiratory parameters. Experiments were conducted with data of 625 subjects without sleep-disordered breathing selected from the SHHS dataset. Compared to previous studies, our method considers results of neighboring epochs classification and epoch position over record time. The method demonstrates Cohen's kappa of 0.57 ± 0.13 and the accuracy of 71.4 ± 8.6 %. The results might contribute to the development of screening tools for diagnostics, prevention, and management of sleep disorders.

Tacrolimus Predose Concentration Is Associated With Hypertension in Pediatric Liver Transplant Recipients

BACKGROUND

The aim of the study was to analyze the incidence of hypertension in pediatric liver transplantation (LT) recipients using ambulatory blood pressure measurements (ABPM) and to identify factors associated with hypertension. We also investigated whether hypertension or tacrolimus predose concentration (TAC C0) was associated with increased left ventricular (LV) wall thickness.

PATIENTS AND METHODS

On a retrospective longitudinal base, we included 39 pediatric LT recipients. Median time since transplantation was 65 months (range: 11-183). Two consecutive ABPM were analyzed with a median time interval of 13 months. Data from echocardiographic evaluation parallel to the baseline ABPM were analyzed. All patients except 1 were prescribed tacrolimus. The median TAC C0 was 4 ng/mL (range 0.9-11.2). Univariate and multivariate logistic regression models were fitted to identify factors associated with systolic and diastolic hypertension and LV wall thickness.

RESULTS

Twenty-two of 39 children were hypertensive at baseline and 19 of 32 were hypertensive at follow-up. At baseline 10 (26%) children had masked systolic hypertension. TAC C0 was associated with systolic (P = 0.007, Exp(B) 2.02, 95% CI 1.2-3.3) and diastolic (P = 0.044, Exp(B) 1.48, 95% CI 1.0-2.2) hypertension. LV wall thickness was increased in children after LT compared with healthy population, but it was not associated with hypertension or TAC C0.

CONCLUSIONS

Given the high prevalence of masked hypertension, ABPM should be performed in all pediatric LT recipients. Systolic and diastolic hypertension is associated with TAC C0; therefore, children with a higher target TAC C0 require a more intensive blood pressure surveillance.

Differences in night-time and daytime ambulatory blood pressure when diurnal periods are defined by self-report, fixed-times, and actigraphy: Improving the Detection of Hypertension study

OBJECTIVES

To determine whether defining diurnal periods by self-report, fixed-time, or actigraphy produce different estimates of night-time and daytime ambulatory blood pressure (ABP).

METHODS

Over a median of 28 days, 330 participants completed two 24-h ABP and actigraphy monitoring periods with sleep diaries. Fixed night-time and daytime periods were defined as 0000-0600 h and 1000-2000 h, respectively. Using the first ABP period, within-individual differences for mean night-time and daytime ABP and kappa statistics for night-time and daytime hypertension (systolic/diastolic ABP≥120/70 mmHg and ≥135/85 mmHg, respectively) were estimated comparing self-report, fixed-time, or actigraphy for defining diurnal periods. Reproducibility of ABP was also estimated.

RESULTS

Within-individual mean differences in night-time systolic ABP were small, suggesting little bias, when comparing the three approaches used to define diurnal periods. The distribution of differences, represented by 95% confidence intervals (CI), in night-time systolic and diastolic ABP and daytime systolic and diastolic ABP was narrowest for self-report versus actigraphy. For example, mean differences (95% CI) in night-time systolic ABP for self-report versus fixed-time was -0.53 (-6.61, +5.56) mmHg, self-report versus actigraphy was 0.91 (-3.61, +5.43) mmHg, and fixed-time versus actigraphy was 1.43 (-5.59, +8.46) mmHg. Agreement for night-time and daytime hypertension was highest for self-report versus actigraphy: kappa statistic (95% CI) = 0.91 (0.86,0.96) and 1.00 (0.98,1.00), respectively. The reproducibility of mean ABP and hypertension categories was similar using each approach.

CONCLUSION

Given the high agreement with actigraphy, these data support using self-report to define diurnal periods on ABP monitoring. Further, the use of fixed-time periods may be a reasonable alternative approach.

Plasma brain-derived neurotrophic factor and reverse dipping pattern of nocturnal blood pressure in patients with cardiovascular risk factors

CONTEXT

Basic studies have shown that brain-derived neurotrophic factor (BDNF) has critical roles in the survival, growth, maintenance, and death of central and peripheral neurons, while it is also involved in regulation of the autonomic nervous system. Furthermore, recent clinical studies have suggested potential role of plasma BDNF in the circulatory system.

OBJECTIVE

We investigated the mutual relationships among plasma BDNF, patterns of nocturnal blood pressure changes (dippers, non-dippers, extra-dippers, and reverse-dippers), and cardiac autonomic function as determined by heart rate variability (HRV).

DESIGN

This was a cross-sectional study of patients registered in the Hyogo Sleep Cardio-Autonomic Atherosclerosis (HSCAA) Study from October 2010 to November 2012.

PATIENTS

Two-hundred fifty patients with 1 or more cardiovascular risk factor(s) (obesity, smoking, presence of cardiovascular event history, hypertension, dyslipidemia, diabetes mellitus, chronic kidney disease) were enrolled.

RESULTS

Plasma BDNF levels (natural logarithm transformed) were significantly (p = 0.001) lower in reverse-dipper patients (7.18±0.69 pg/ml, mean ± SD, n = 36) as compared to dippers (7.86±0.86 pg/ml, n = 100). Multiple logistic regression analysis showed that BDNF (odds ratios: 0.417, 95% confidence interval: 0.228-0.762, P = 0.004) was the sole factor significantly and independently associated with the reverse-dippers as compared with dippers. Furthermore, plasma BDNF level was significantly and positively correlated with the time-domain (SDNN, SDANN5, CVRR) and frequency-domain (LF) of HRV parameters. Finally, multiple logistic regression analyses showed that the relationship between plasma BDNF and the reverse-dippers was weakened, yet remained significant or borderline significant even after adjusting for HRV parameters.

CONCLUSIONS

Low plasma BDNF was independently associated with patients showing a reverse-dipper pattern of nocturnal blood pressure, in which an imbalance of cardiac autonomic function may be partly involved.

The dilemma of nocturnal blood pressure

During the past decades, blood pressure (BP) measurement technique has evolved rapidly from the traditionally manual measuring to fully automatic monitoring. In terms of management of BP, there have been tremendous changes from the controlling of daytime BP, nondipping pattern to nocturnal BP (NBP). Since the focus has turned to NBP, a number of dilemmas of NBP measurement have gradually emerged in clinical practice and research settings, including methods for monitoring NBP, different period definition of nocturnal time, different diagnostic thresholds of abnormal NBP, whether to control abnormal NBP, and how to manage abnormal NBP. Currently, these issues have hindered progress in the appropriate management of hypertensive patients. Therefore, the purpose of this review is to concisely discuss the dilemmas of NBP.

Blood pressure measurement: clinic, home, ambulatory, and beyond

Blood pressure traditionally has been measured in the clinic setting using the auscultatory method and a mercury sphygmomanometer. Technologic advances have led to improvements in measuring clinic blood pressure and allowed for measuring blood pressures outside the clinic. This review outlines various methods for evaluating blood pressure and the clinical utility of each type of measurement. Home blood pressures and 24-hour ambulatory blood pressures have improved our ability to evaluate the risk of target-organ damage and hypertension-related morbidity and mortality. Measuring home blood pressures may lead to more active participation in health care by patients and has the potential to improve blood pressure control. Ambulatory blood pressure monitoring enables measuring nighttime blood pressures and diurnal changes, which may be the most accurate predictors of risk associated with elevated blood pressure. Additionally, reducing nighttime blood pressure is feasible and may be an important component of effective antihypertensive therapy. Finally, estimating central aortic pressures and pulse wave velocity are 2 of the newer methods for assessing blood pressure and hypertension-related target-organ damage.

Chemoreceptors, baroreceptors, and autonomic deregulation in children with obstructive sleep apnea

Obstructive sleep apnea (OSA) is highly prevalent sleep disorder of breathing in both adults and children that is fraught with substantial cardiovascular morbidities, the latter being attributable to a complex interplay between intermittent hypoxia (IH), episodic hypercapnia, recurrent large intra-thoracic pressure swings, and sleep disruption. Alterations in autonomic nervous system function could underlie the perturbations in cardiovascular, neurocognitive, immune, endocrine and metabolic functions that affect many of the patients suffering from OSA. Although these issues have received substantial attention in adults, the same has thus far failed to occur in children, creating a quasi misperception that children are protected. Here, we provide a critical overview of the evidence supporting the presence of autonomic nervous system (ANS) perturbations in children with OSA, draw some parallel assessments to known mechanisms in rodents and adult humans, particularly, peripheral and central chemoreceptor and baroreceptor pathways, and suggest future research directions.

[Effects of nighttime and daytime interval definition on blood pressure and dipping in patients referred for ambulatory blood pressure measurement]

Ambulatory blood pressure monitoring (ABPM) has become indispensable for the diagnosis and control of hypertension. However, no consensus exists on how daytime and nighttime periods should be defined.

OBJECTIVE

To compare daytime and nighttime blood pressure (BP) defined by an actigraph and by body position with BP resulting from arbitrary daytime and nighttime periods.

PATIENTS AND METHOD

ABPM, sleeping periods and body position were recorded simultaneously using an actigraph (SenseWear Armband(®)) in patients referred for ABPM. BP results obtained with the actigraph (sleep and position) were compared to the results obtained with fixed daytime (7a.m.-10p.m.) and nighttime (10p.m.-7a.m.) periods.

RESULTS

Data from 103 participants were available. More than half of them were taking antihypertensive drugs. Nocturnal BP was lower (systolic BP: 2.08±4.50mmHg; diastolic BP: 1.84±2.99mmHg, P<0.05) and dipping was more marked (systolic BP: 1.54±3.76%; diastolic BP: 2.27±3.48%, P<0.05) when nighttime was defined with the actigraph. Standing BP was higher (systolic BP 1.07±2.81mmHg; diastolic BP: 1.34±2.50mmHg) than daytime BP defined by a fixed period.

CONCLUSION

Diurnal BP, nocturnal BP and dipping are influenced by the definition of daytime and nighttime periods. Studies evaluating the prognostic value of each method are needed to clarify which definition should be used.

Challenges of measuring diurnal cortisol concentrations in a large population-based field study

OBJECTIVES

Longitudinal examinations of associations between daily stress, diurnal cortisol concentrations, and physiological parameters in population-based studies are needed. This study evaluates issues related to consent, collection, and protocol adherence for a low-burden saliva collection protocol.

METHODS

In the 2007 pretest (n=193) for Wave IV of the National Longitudinal Study of Adolescent Health (Add Health) a three-sample, one-day, unsupervised saliva collection protocol was pilot tested. Embedded experiments allowed for examination of adherence and effects of monetary incentives.

RESULTS

Although most (97%) study participants consented to collection, only about 80% actually mailed back samples. Use of a time-stamping TrackCap allowed comparison of self-reported and stamp-recorded collection times. Of returned samples, self-report of collection time was missing for about a quarter, and only about one in three respondents (of those for whom adherence was calculable) fully adhered to the collection protocol, indicating significant potential for bias. Consent, return, and protocol adherence were unrelated to key sociodemographic characteristics, and did not improve with higher monetary incentives or knowledge of being monitored.

CONCLUSIONS

Despite the relatively low-burden collection protocol and use of multiple strategies thought to improve collection and protocol adherence, response and adherence were poor, leading to a decision to drop cortisol measurement from the Wave IV Add Health protocol. Large field studies should carefully evaluate the feasibility of collection and protocol adherence for unsupervised collection protocols before implementing costly, and potentially unusable, biological measurements.

Actimeter-derived sleep and wake data and nocturnal ambulatory blood pressure estimation in subjects with stroke and transient ischaemic attack

BACKGROUND/AIMS

Abnormalities in nocturnal blood pressure control identified using ambulatory blood pressure monitoring are associated with adverse cardiovascular outcomes. Sleep and wake episodes during such studies are usually identified by means of sleep diaries but these may be inaccurate in stroke patients. We performed a study to determine whether sleep-wake data obtained using wrist-mounted actimeters would significantly influence the results of routinely performed nocturnal ambulatory blood pressure monitoring when compared with diary-based sleep-wake recording and fixed time-period data.

METHODS

Actimetry was performed using a wrist-mounted device during routine ambulatory blood pressure monitoring in subjects who had suffered a transient ischaemic attack or stroke. The mean nocturnal blood pressure readings were calculated using sleep data derived from actimetry and diaries and compared for a fixed time period from 11:00 pm to 8:00 am.

RESULTS

Twenty subjects (mean age 68 years, and 13 female) were studied. Patients were found to have slept for a median of six-hours (one- to eight-hours) by diary and five-hours (zero- to eight-hours) by actimeter data. Diary and actimeter data agreed in 69% of recordings. The mean sleeping systolic blood pressure was lower when calculated by actimeter data than by diary data (119·6 mmHg vs. 123·2 mmHg, P=0·049, paired t-test) but there was no significant difference in diastolic blood pressure. The mean nocturnal blood pressure calculated from 11:00 pm to 7:00 am was higher than sleeping blood pressure calculated from diary data. (mean systolic blood pressure: 127·6 mmHg vs. 123·6 mmHg, P=0·065; mean diastolic blood pressure 69·0 vs. 64·0, P=0·028).

CONCLUSION

Calculation of nocturnal and sleeping blood pressure is lower in subjects with stroke and transient ischaemic attack when objective actimeter-derived sleep/wake data are used.

The definition of daytime and nighttime influences the interpretation of ABPM in children

To test if an arbitrary definition of day and night periods that differs to patient-reported awake and sleep periods leads to inaccuracies in interpretation of ambulatory blood pressure monitoring (ABPM). A single-center, retrospective review was performed comparing three different methods to classify day and night periods following a single 24-h ABPM: method A: Patient's record during monitoring; method B: 7:00 am to 11:00 pm day and 11:00 pm to 7:00 am night; method C: 8:00 am to 8:00 pm day and midnight to 6:00 am night. We included 149 studies in 149 children with a mean ± SD age of 13.0 ± 3.4 years. Reported sleep duration was 9.2  ± 1.3 h. Significant differences resulted between three methods for the means of several ambulatory BP parameters including indexed BP values during day, BP load, and nocturnal dipping status. During monitoring [median (range)], 7.5% (0.0-27.5%) readings were misclassified using method B and 0.0% (0.0-20.0%) using method C (p < 0.0001). This misclassification resulted in change of hypertension status for 11.4% (17/149) patients using method B and 9.4% (14/149) patients using method C (p = 0.70). Misclassification of measurements during ABPM can introduce significant errors in its interpretation. The clinical impact of these findings needs further evaluation in larger prospective studies.

Pitfalls in the measurement of the nocturnal blood pressure dip in adolescents with type 1 diabetes

OBJECTIVE

The purpose of this study was to screen adolescents with type 1 diabetes using ambulatory blood pressure monitoring (ABPM) to 1) test the hypothesis that using a preset sleep time results in an overdiagnosis of abnormal nocturnal dipping in systolic blood pressure and 2) assess the reproducibility of an abnormal nocturnal systolic blood pressure dip.

RESEARCH DESIGN AND METHODS

For aim 1, ABPM from 53 adolescent patients with type 1 diabetes was reviewed. Nocturnal dips in systolic blood pressure calculated by actual sleep time were compared with those from a preset sleep time. For aim 2, blood pressure monitoring from 98 patients using actual reported sleep time was reviewed. Reproducibility of the nocturnal dip in systolic blood pressure was assessed in a subset of "nondippers."

RESULTS

For aim 1, the actual mean +/- SE decline in nocturnal systolic blood pressure was 11.6 +/- 4.7%, whereas the mean decline in nocturnal systolic blood pressure calculated using the preset sleep time was 8.8 +/- 4.9% (P < 0.0001). For aim 2, 64% of patients had a normal nocturnal decline in systolic blood pressure (14.9 +/- 3.1% mmHg), whereas 36% had an abnormal dip (5.7 +/- 2.8% mmHg). Repeat ABPM performed in 22 of the 35 nondippers revealed that only 36% had abnormal systolic dipping confirmed on the repeat ABPM.

CONCLUSIONS

The use of actual reported sleep time is required to accurately determine the nocturnal dip in systolic blood pressure. Repeating ABPM in nondippers is essential to confirm this abnormality.

The impact of sleep on ambulatory blood pressure of female caregivers providing home care in Japan: an observational study

BACKGROUND

Elderly family caregivers are presumed to be susceptible to having various health problems. However, biomedical indicators of health in these caregivers are rarely examined.

OBJECTIVE

To examine the effect of sleep quality, measured by hours of sleep and the number of times leaving bed, on various blood pressure parameters in elderly caregivers.

DESIGN

Observational study.

SETTING

Northern Japan.

PARTICIPANTS

Seventy-eight female family caregivers.

METHODS

Ambulatory blood pressure was monitored at 30-60-min intervals for a 24-h period. An actigraph was used to determine sleep/wake status. Face-to-face interviews were conducted to obtain home care and demographic information, and self-administered questionnaires were used to collect information on activities in a 24-h period.

RESULTS

The mean age of the caregivers was 62.5+/-9.6 years, and the mean hours of sleep were 7.3. Out of 78 caregivers, 19 were on antihypertensive medication. Of the remaining 59, this study found 45.8% to be hypertensive, with the mean maximum systolic pressure exceeding 180mmHg. The hours of sleep at night and for the 24-h period were inversely associated with the mean systolic blood pressure. The majority of caregivers on antihypertensive medication also had high blood pressure.

CONCLUSIONS

This study suggests the importance of 24-h ambulatory blood pressure monitoring for elderly caregivers, so as to screen for hypertension as well as to monitor the effectiveness of antihypertensive medication.

Activity in the chronically critically ill

Although therapeutic activity prevents functional decline and reduces mortality, little is known about typical levels of activity among intensive care unit (ICU) patients. This report of a preliminary study describes typical therapeutic activity and compares the use of two measures of activity in a small sample of chronically critically ill adults. Type, frequency, and duration of therapeutic activity were measured simultaneously with direct observation and actigraphy. The only consistent activity documented was turning (frequency: 3 turns/8 hours; duration: mean average of 11 minutes). Analysis demonstrated acceptable agreement between the two measures of activity for both frequency and duration of therapeutic but not for type of activity. Congruence between measures for duration of activity was also supported. This study provides information for investigators and practitioners who are interested in measuring or implementing therapeutic activity in selected critically ill adults.

The “Nondipper” Elderly: A Clinical Entity or a Bias?

OBJECTIVES

To determine the prevalence of nondipper (ND) blood pressure profile in the elderly and to ascertain whether the ND pattern of ambulatory blood pressure in the elderly is an artifact or represents a specific clinical entity.

DESIGN

Cross-sectional, observational study.

SETTING

Cardiovascular diagnostic center, division of geriatrics, secondary care, institutional practice.

PARTICIPANTS

Sixty-five consecutive community-dwelling elderly hypertensive patients referred to the cardiovascular center.

MEASUREMENTS

The patients underwent actigraphy and ambulatory blood pressure monitoring and completed a sleep assessment questionnaire. Patients were divided based on the night-time decrease in blood pressure (>10%: "dippers" (n=19); <10%: "NDs" (n=46)).

RESULTS

Nondippers displayed poorer quality of sleep, as demonstrated objectively by actigraphic data; they obtained a higher mean score+/-standard deviation on the sleep questionnaire (4.6+/-2.9 vs 3.0+/-1.1, P=.030) and were taking more benzodiazepines (33.1% vs 10.7%, P=.035), indicating that their usual sleep quality was worse than that of dippers. Multivariate analysis showed a strong correlation between nondipper profile and quality of sleep and also with comorbidity, total number of drugs being taken, and pulse pressure.

CONCLUSION

Actigraphy demonstrates impaired sleep in the nondipper elderly. Nevertheless, the nondipping pattern seems independent of the discomfort of cuff-inflation during the night and occurs in association with higher comorbidity and polypharmacy; therefore, it cannot be considered a "bias," but is related to detrimental clinical conditions that should be studied in depth.

Salivary cortisol sampling compliance: comparison of patients and healthy volunteers

OBJECTIVE

Problems of compliance with in vivo data collection and treatment protocols have been identified. This study investigated compliance with salivary cortisol sampling in a 7-day protocol. Impact of non-compliance on cortisol data was evaluated.

METHODS

Female fibromyalgia patients were matched with healthy female volunteers and randomized to Aware or Unaware conditions regarding objective monitoring of their sampling compliance. The protocol entailed collecting five saliva samples at prescribed times on each of 7 consecutive days. Participants self-reported time of each sample, and electronic monitor caps provided an objective date and time stamp of each sample.

RESULTS

Objective compliance among participants unaware of monitoring was 71%, though their self-reported compliance was 93%. Aware participants' objective compliance was 90% which was consistent with self-reported compliance of 93%. Within-subject comparison of early morning rise and day slope of cortisol for compliant and non-compliant samples found significant differences with non-compliant samples resulting in flatter slopes. Patients were somewhat more compliant than healthy volunteers. Slight decrements in compliance were found for the afternoon sample (1600 h) and for the last 3 days of sampling. Compliance did not differ on weekdays versus weekends.

CONCLUSIONS

Self-report of compliance in a salivary cortisol sampling protocol substantially overestimates actual compliance in the absence of objective monitoring. Non-compliance with the sampling protocol results in cortisol data that significantly differs from compliant data. Awareness of electronic monitoring of sampling results in satisfactory compliance.

Rest-activity patterns in children with hypopituitarism

OBJECTIVES

Physical lesions in the region of the suprachiasmatic nuclei, which are the site of a circadian clock, result in abnormal circadian rhythmicity in animals, yet the extent of biological rhythm problems in individuals with anatomic or functional lesions in the hypothalamic-pituitary region are largely unknown. To address this issue, we examined patterns of rest and activity of children with hypopituitarism.

METHODS

Children who were between the ages of 2 and 18 years and had the diagnosis of panhypopituitarism were evaluated. Twenty children were studied, including children with septo-optic dysplasia (SOD), congenital hypopituitarism, brain tumors, closed head trauma, and head irradiation. For assessing patterns of activity, individuals wore Actiwatches for 3-4 weeks to measure patterns of gross motor activity.

RESULTS

Seventeen children had normal patterns of rest and activity, with an average period length of 24.01 +/- 0.01 hours. Three children, including 2 with SOD and 1 with a hypothalamic germinoma, showed abnormal activity patterns in which there was not consolidated rest at night. One patient with an optic glioma had nonentrained circadian phase.

CONCLUSIONS

A proportion of children with hypopituitarism have abnormal daily rest-activity patterns. Children with anterior hypothalamic tumors and SOD seem to be at risk for circadian system dysfunction.

Casual blood pressure and ambulatory blood pressure measurement in children

Some epidemiological studies on blood pressure among children and adolescents have revealed that blood pressure levels in childhood are the strongest predictors of adult blood pressure levels. In the adult population, hypertension causes a two to threefold increase in an individual's risk of cardiovascular morbidity. Cardiovascular risk depends on blood pressure itself, coexistent risk factors and whether there is hypertensive end-organ damage. Therefore, accuracy in determining blood pressure is essential and a standardized protocol should be considered for blood pressure measurement, which would make the comparison of results obtained by different studies in different countries possible. This article reviews the main determinants of accuracy for casual and ambulatory blood pressure measurements in children.

Actigraphy assessment of sleep disturbance in patients with atopic dermatitis: an objective life quality measure

BACKGROUND

Patients with atopic dermatitis (AD) frequently report compromised quality of life because of disturbed sleep and daytime fatigue secondary to their skin disease, but few studies provide objective measurement of sleep change in this population.

OBJECTIVE

The purpose of this investigation was to contrast subjective and objective measures of sleep quality in patients with AD.

METHODS

Fourteen adult patients with AD and 14 adult control subjects with no skin disease wore actigraphs for 1 week and completed questionnaires about sleep, itch, and quality of life.

RESULTS

As measured by self-report and actigraphy, the AD group slept more poorly and reported more daytime fatigue than the control group. Actigraphy alone was correlated with itch and quality of life and was able to discriminate movement during sleep, number of awakenings, minutes asleep, and minutes awake.

CONCLUSIONS

Results from this study demonstrate that sleep is significantly compromised in patients with AD. Patients' perception of their sleep provides less detail and accuracy than actigraphy. The actigraph is an objective, unobtrusive measure of sleep at home in patients with skin disease and can provide an important outcome measure in clinical trials.

Does graded activity increase activity? A case study of chronic fatigue syndrome

The reliance on self-report outcome measures in clinical trials of graded activity-oriented cognitive-behavior therapy in chronic fatigue syndrome (CFS) makes it difficult to draw definitive conclusions about actual behavioral change. The participant in this case study was a 52-year-old married male with CFS who was working full-time. Outcome measures included a step counter to objectively measure physical activity as well as a daily diary measure of exercise activity and in vivo ratings of perceived energy, fatigue, and affect. The following psychometric instruments were also used: the CFS Symptom Inventory, the SF-36, the Beck Depression Inventory, and the Beck Anxiety Inventory. The 26-session graded activity intervention involved gradual increases in physical activity. From baseline to treatment termination, the patient's self-reported increase in walk time from 0 to 155 min a week contrasted with a surprising 10.6% decrease in mean weekly step counts. The final follow-up assessment revealed a "much improved" global rating, substantial increases in patient-recorded walk time and weight lifting intensity, yet a relatively modest increment in weekly step counts. It appeared that improvement was associated with mood-enhancing, stress-reducing activities that were substituted for stress-exacerbating activities.