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Biomedical subjects

M D Fotherby

Publications and source records attributed to M D Fotherby.

At least 37 records · Page 2Linked to original sources
PubMed1995

Reproducibility of the circadian systolic blood pressure variation in the elderly.

OBJECTIVES: To establish the reproducibility of the nocturnal systolic blood pressure (SBP) change in elderly subjects and to examine the use of cumulative sums (cusums) analysis in the assessment of circadian SBP variation. SUBJECTS: Forty-two untreated elderly subjects (35 hypertensive, 7 normotensive) of mean age 75.5 years from the hypertension clinic at a large teaching hospital participated in a reproducibility study. METHODS: Twenty-four-hour ambulatory blood pressure monitoring was performed and repeated at a median interval of 2 months (range 2 weeks to 9 months). OUTCOME MEASURES: Reproducibility of circadian SBP variation from fixed time analysis of day-night SBP difference and from cusums-based parameters. RESULTS: Twenty-four-hour SBP values were highly reproducible with a coefficient of variation of 5.8%. However, the day-night SBP difference for fixed time periods was poorly reproducible, with a coefficient of variation > 130%. A substantial proportion of subjects (36-43%) altered their 'dipping status' between visits. The use of cusums analysis improved the reproducibility of measures of circadian SBP change (cusums plot height and maximum circadian variation) with coefficients of variation falling to 40 and 38%, respectively. CONCLUSIONS: The use of fixed time definitions results in poor reproducibility of the circadian SBP change in the elderly, which will lead to regression dilution bias when studying the relationship of circadian SBP variation to outcome measures in hypertension. The notion of dipping and non-dipping circadian blood pressure patterns should be abandoned in favour of more reproducible cusums-based measures of circadian blood pressure variation.

Aged↗
PubMed1995

Withdrawal of antihypertensive therapy in the elderly. The issues.

Studies of antihypertensive drug withdrawal suggest that at least 20% of selected older patients with hypertension can remain normotensive without drug treatment for periods of up to 5 years. Success of drug withdrawal is greater in those patients controlled on low dose monotherapy who have low on-treatment blood pressure (BP), are not overweight and who have no ECG evidence of left ventricular hypertrophy. Compliance with lifestyle advice may increase the chance of successful drug withdrawal. Unfortunately, many older hypertensive patients have poorly controlled BP despite treatment with antihypertensive drugs, and are overweight. These factors limit opportunities for drug withdrawal although they may not be so much of a problem in the very elderly. Patient who could be considered for a trial of antihypertensive drug withdrawal are those unhappy with such therapy who also: (a) have well controlled BP on monotherapy with no significant target organ damage, (b) have 'white-coat' hypertension, or (c) are very elderly (> 80 years). The withdrawal of antihypertensive drugs can improve drug-induced metabolic abnormalities and symptoms, and appears safe providing there is a gradual reduction in drug dosages and close follow-up to detect a return to hypertension.

Aged↗
PubMed1995

Twenty-four-hour ambulatory blood pressure in old and very old subjects.

OBJECTIVE: To compare clinic and 24-h blood pressure levels and profiles in young elderly (aged 65-79 years) and old elderly (aged > or = 80 years) subjects. SUBJECTS AND METHODS: A cross-sectional observational study was conducted on 108 ambulant subjects (51 males) aged 65-95 years with no known history of hypertension, recruited from the community (55%) and hospital outpatients (35%) and inpatients (10%). Three clinic blood pressure measurements were taken, followed by 24-h ambulatory blood pressure monitoring and then a further three clinic measurements, the mean of these being defined as the clinic blood pressure. RESULTS: Clinic systolic blood pressure was significantly higher in females than males (148 +/- 20 versus 136 +/- 23 mmHg, P = 0.02), but 24-h systolic blood pressure was similar. Mean 24-h and daytime blood pressure levels were significantly lower than clinic blood pressure in females but in males only 24-h systolic blood pressure was lower than the clinic level. In young elderly compared to old elderly females the clinic-daytime ambulatory systolic blood pressure difference was significantly reduced (14 +/- 22 versus 1 +/- 17 mmHg, respectively; P = 0.04). A significant nocturnal systolic/diastolic blood pressure fall was seen in young elderly and old elderly males (9 +/- 12/7 +/- 7 versus 6 +/- 11/7 +/- 8 mmHg) but in females the nocturnal systolic blood pressure fall was inversely related to age (r = -0.32, P = 0.02). CONCLUSIONS: The white-coat effect is common in young elderly females, but uncommon in very elderly females and males aged > or = 65 years; a decline in casual blood pressure in the very elderly may partly arise from a reduction in the white-coat effect. Nocturnal blood pressure falls also decline in the very elderly, especially in females.

Aged↗
PubMed1994

Can topical zinc accentuate tuberculin reactivity in the elderly?

We examined the effect of topical zinc on Heaf tests in 58 elderly hospitalized patients in a double-blind study. Plasma zinc levels were measured. Thirty-eight subjects (66%) had negative reactions with placebo ointment. Fourteen of these negative responders (37%) had positive reactions with topical zinc ointment; 12 (32%) had weakly positive reactions and 12 remained negative. There was no significant difference in the plasma zinc levels between the different grades of topical zinc effect in the negative responders. Zinc deficiency is therefore unlikely to account for the observed booster effect of topical zinc on tuberculin reactivity.

Administration, Topical↗
PubMed1994

Eligibility of acute stroke patients for pharmacological therapy.

The aims of this study were to analyse the characteristics of patients with acute stroke and to ascertain the number of patients meeting eligibility criteria commonly applied in clinical trials of pharmacological agents for ischaemic stroke. Details of all consecutive admissions with a diagnosis of acute stroke (n = 410, 55% female, mean age 77, range 22-99 years) admitted over a 12-month period to a district general hospital were recorded. Major exclusion criteria used in acute stroke trials were applied to data collected from the study patients. Exclusion criteria were met by 386 (94%) stroke patients, 188 (46%) had admission delay > 12 hours, 85 (21%) had pre-existing major disability, 80 (20%) minor stroke, 66 (15%) had coexisting severe illness, 51 (12%) were unconscious, and 30 (7%) had major electrolyte or ECG abnormalities. One hundred and five (26%) had two or more exclusion criteria. The majority of acute stroke patients admitted to a district general hospital would be likely to be excluded from most current pharmacological treatment studies.

Adult↗
PubMed1994

The changes in blood pressure after acute stroke: abolishing the 'white coat effect' with 24-h ambulatory monitoring.

OBJECTIVES: To assess the changes in 24-h and casual blood pressure (BP) levels following hospitalization for acute stroke. DESIGN: Prospective study of patients admitted with acute hemispheric stroke and hospitalized controls using casual and 24-h BP monitoring. SETTING: Medical wards in a large teaching hospital. SUBJECTS: Thirty-three patients (median age 77 years, 17 male) and 21 control subjects admitted non-acutely. INTERVENTIONS: All subjects underwent 24-h BP monitoring within 24 h of stroke onset (patients) or admission (controls) and again at 1 week. Casual BPs were recorded over the same period. MAIN OUTCOME MEASURES: The change in BP over the first week in each group. Eleven stroke subjects had 24-h BP monitoring repeated at 6 months. RESULTS: In the stroke group, 24-h systolic BP (SBP) fell by 7 mmHg (95% CI, 0 to 14 mmHg; P < 0.05) and diastolic BP (DBP) by 3 mmHg (95% CI, 0 to 6 mmHg; P < 0.02) over the first week. Mean 24-h BP levels in the control group did not change during this period. However, casual BP recordings fell in both stroke (18/12 mmHg) and control (19/9 mmHg) groups. Stroke subjects followed to 6 months showed no further change in 24-h BP (day 7: 137 +/- 17/79 +/- 13 mmHg; month 6: 138 +/- 16/78 +/- 11 mmHg). CONCLUSIONS: Although there was a large fall in causal BPs seen in both groups there was only a small, but a significant fall in mean 24-h BP over the first week following hemispheric stroke that was not seen in control subjects. Although the 'white coat effect' and admission to hospital play an important part in the high casual BP observed in the days following acute stroke they are unlikely to be the sole factors.

Acute Disease↗
PubMed1994

Orthostatic hypotension and anti-hypertensive therapy in the elderly.

The effect of withdrawing or continuing anti-hypertensive therapy on orthostatic blood pressure change in elderly hypertensive subjects was examined. Subjects meeting criteria for therapy withdrawal had supine and standing blood pressure measurements taken on treatment, and at 1, 3, 6, 9 and 12 months off treatment whilst receiving standard non-pharmacological advice to lower blood pressure. Subjects not meeting blood pressure criteria for treatment withdrawal or were unwilling to stop treatment had blood pressure measurements taken after 6 and 12 months whilst also receiving non-pharmacological advice. Orthostatic hypotension was defined as a mean systolic blood pressure fall > or = 20 mmHg on standing from a supine position. Forty-seven subjects (median age 76 years, range 65-84 years) had treatment withdrawn. Thirteen subjects (median age 73 years, range 68-82 years) continued on their treatment. Twelve months after treatment withdrawal there was a significant reduction in the number demonstrating orthostatic hypotension from 11 (23%) to four (11%) (P < 0.05), whilst the group continuing on treatment showed no change. In the withdrawal group those with orthostatic hypotension on treatment (n = 11) were older (79 versus 74 years, P = 0.05), had higher prewithdrawal systolic blood pressure (164 +/- 21 versus 147 +/- 17 mmHg, P = 0.02) compared to those without, although there was no difference in body mass index, gender, number or type of anti-hypertensive drugs taken. In elderly hypertensive subjects withdrawal of anti-hypertensive therapy and institution of non-pharmacological treatment can over several months reduce the prevalence of orthostatic hypotension.

Aged↗
PubMed1994

Clinic and 24h blood pressure in elderly treated hypertensives with postural hypotension.

The objectives of this study were to determine the prevalence of, and factors associated with, postural hypotension (PH) in elderly treated hypertensive subjects, to examine the 24h BP profile in those subjects with and without PH and to determine the effects of antihypertensive treatment withdrawal on the prevalence and symptoms of PH. Eighty-six subjects (mean age +/- standard deviation 76 +/- 6 years) on antihypertensive drug therapy for > 6 months had three clinic BP measurements taken in supine and standing positions followed by 24h ambulatory BP monitoring. Forty-seven subjects underwent repeat BP measurement five weeks after withdrawal of antihypertensive medication and institution of standard nonpharmacological methods. Twenty-six (30%) of the 86 subjects exhibited PH (defined as SBP fall on standing > or = 20 mmHg) within three minutes of standing. Supine clinic and 24h SBP and DBP, age and presence of previous cardiovascular events were similar in the groups with and without PH. There was a significant correlation between the orthostatic BP fall for all subjects and day-night SBP difference (r = -0.30, P = 0.01) and urinary sodium:creatinine ratio (r = -0.33, P = 0.04). Multiple regression analysis revealed only the day-night SBP difference was a significant predictor of orthostatic BP change. In the PH group, 19 subjects had treatment withdrawn resulting in a reduction of 58% (P > 0.001) in those continuing to demonstrate PH. If indicated a trial of antihypertensive drug treatment withdrawal could reduce the risk of PH; the additional benefit of instituting nonpharmacological therapy in reducing BP and orthostatic hypotension warrants further assessment.

Aged↗
PubMed1994

Possibilities for antihypertensive drug therapy withdrawal in the elderly.

The aims of this study were to determine: (1) the proportion of elderly hypertensive subjects currently attending a hospital hypertension clinic suitable for a trial of antihypertensive drug withdrawal, (2) the proportion of suitable patients who can be successfully withdrawn from drug therapy while receiving nonpharmacological advice, and (3) the factors associated with successful withdrawal. One hundred and five consecutive hypertensive subjects, 53% female, mean age 76 years (range 65-84 years) on pharmacological antihypertensive therapy for > 1 year were studied, of whom 78 (74%) had a clinic SBP < 175 mmHg and DBP < 100 mmHg. Subjects with recent myocardial infarction or stroke or with symptoms of ischaemic heart disease were excluded. Antihypertensive drug therapy was withdrawn in this group and nonpharmacological advice to lower BP was instituted. Clinic BP and weight were subsequently recorded monthly for 12 months in all subjects and at every three months in those who had a possible follow-up period of 24 months. The 24h ambulatory BP was measured at baseline and repeated one month off therapy; 24h urine electrolytes were also assessed at baseline and at 12 months or before restarting drug therapy. Seventy-four (70%) subjects had a potential follow-up of 12 months (four were withdrawn from the study) and 64 were available for two years of follow-up. Antihypertensive treatment was restarted if SBP > or = 160 mmHg and/or DBP > or = 90 mmHg on two consecutive visits. After 12 months, 20 (25%) of those withdrawn remained normotensive, the majority restarting therapy did so in the first three months.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Microalbuminuria in elderly hypertensives: reproducibility and relation to clinic and ambulatory blood pressure.

OBJECTIVE: To examine the short-term reproducibility of urinary albumin measurements and the relation of urinary albumin excretion to the clinic and ambulatory blood pressure levels in elderly untreated hypertensive subjects. SETTING: Outpatient hypertension clinic of a District General Hospital. MAIN OUTCOME MEASURES: The within-patient reproducibility of 24-h urinary microalbumin and electrolyte excretion and relation to 24-h and clinic blood pressure levels. PATIENTS: Sixty-four untreated elderly hypertensives (mean age 74.7 years, range 64-82) with systolic blood pressure > or = 160 mmHg or diastolic blood pressure > or = 95 mmHg, or both, were recruited from general practitioner clinics and current outpatient attenders. The patients had not received antihypertensive treatment for at least 4 weeks. METHODS: The clinic and 24-h non-invasive ambulatory blood pressures were recorded with a simultaneous 24-h urine collection for measurement of the urinary albumin and electrolyte excretion. Thirty-seven subjects performed two consecutive 24-h urine collections for an assessment of the short-term reproducibility of the albumin and electrolyte excretion. RESULTS: The coefficient of variation of 24-h urinary albumin excretion was 62%, and for the albumin:creatinine ratio 52%, compared with 19% for sodium and 15% for potassium excretion. The urinary albumin excretion correlated with clinic systolic blood pressure (r = 0.33, P = 0.01) and with 24-h ambulatory systolic (r = 0.48, P < 0.001) and diastolic (r = 0.32, P = 0.01) blood pressure. The subjects with microalbuminuria (24-h urinary albumin excretion in the range 30-300 mg) had higher clinic and ambulatory blood pressures than those with lower levels of albumin excretion. CONCLUSIONS: The low day-to-day intrasubject reproducibility in the 24-h urinary albumin excretion considerably reduces the potential value of single collections in the assessment of microalbuminuria in elderly hypertensives. The urinary albumin excretion correlates with the clinic and 24-h ambulatory blood pressures in elderly hypertensives.

Aged↗
PubMed1994

Clinical correlates of left ventricular mass in elderly hypertensives.

We set out to examine the prevalence of echocardiographically-determined left ventricular hypertrophy (LVH) in a hospital-based population of untreated elderly hypertensives and to study the relationship between left ventricular mass index and clinic and 24h ambulatory BP, urinary electrolyte and microalbumin excretion and ECG changes. We studied 52 untreated elderly hypertensives, mean age 76 years, with no evidence of stroke or heart disease. Subjects underwent 24h ambulatory BP recording together with 24h urine collection for electrolytes and microalbumin estimation. A standard ECG was examined for LVH by commonly used criteria. Subjects were examined by 2-dimensional guided M-mode echocardiography; left ventricular mass was calculated from the formula of Devereux and Riechek and corrected for body surface area (left ventricular mass index, LVMI). Mean LVMI was 168 +/- 39 g/m2 for men and 153 +/- 36 g/m2 for women; 43 (83%) subjects had LVH. LVMI was significantly related to clinic SBP (r = 0.27, P = 0.05), ambulatory daytime SBP (r = 0.27, P = 0.05), nighttime SBP (r = 0.41, P = 0.003) and nighttime DBP (r = 0.29, P = 0.04). LVMI was also related to the difference in mean SBP between day and night (r = -0.32, P = 0.02) and subjects with a day-night SBP difference of > or = 10 mmHg (n = 27) had significantly lower LVMI than those with a day-night SBP difference < 10 mmHg (141 +/- 32 g/m2 vs. 176 +/- 35 g/m2, respectively; P = 0.0005). Fifteen subjects had LVH by ECG criteria giving a sensitivity of 28% and specificity of 66%. LVMI was not related to urinary sodium, potassium or albumin excretion. This study shows that in elderly hypertensives it is measures of nighttime BP which are most closely related to LVMI and subjects with a greater nocturnal fall in BP have lower LVMI, presumably reflecting differences in 24h BP load.

Aged↗
PubMed1994

Variation of within visit blood pressure readings at a single visit in the elderly and their relationship to ambulatory measurements.

The value of routinely taking one or several BP readings at a single visit in subjects with an initially elevated BP reading is unclear. The variation of sequential BP readings in the elderly, who often have a disproportionate increase in SBP compared with DBP, has received little attention. In addition, no attempt has been made to relate the various BP readings obtained to a subject's ambulatory daytime BP. The aim of this study was to examine the variation in BP between one, two or three readings at a single visit in elderly subjects with elevated BPs and to compare these readings with those obtained from daytime ambulatory BP monitoring (ABPM). Sixty-nine subjects, mean age 76 years (range 66-86 years) with at least one SBP reading > 150 mmHg and who had undergone a minimum of two previous clinic visits for BP measurement by the same physician were included. Following five minutes rest three supine BP readings were taken, spaced two minutes apart, using a Hawksley random zero sphygmomanometer. Seventeen subjects underwent home 24h ABPM commencing immediately after the clinic BP readings. Clinic SBP fell from first to third reading by 11 mmHg (95% Cl 9-13 mmHg, P < 0.001) and from first to second readings by 6 mmHg (Cl 4-8 mmHg, P < 0.01). There was no change in mean DBP between readings. In 85% of readings first SBPs were higher than the second.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

Repeatability and relationship between arterialized catecholamines and blood pressure in elderly subjects.

Little work has been conducted to assess repeatability and relation of arterialized plasma catecholamines to blood pressure in elderly subjects. We studied 19 untreated elderly patients with essential hypertension and 19 matched normotensives on two occasions one week apart. After prolonged supine rest, BP, pulse rate and arterialized plasma catecholamine levels were measured. Systolic (SBP) and diastolic (DBP) blood pressure, plasma adrenaline (A) and noradrenaline (NA) repeatabilities were similar for the hypertensive and normotensive groups. Mean supine pulse rate was significantly higher in the hypertensive group as were arterialized plasma A, but not NA, levels. For the whole group there was a significant univariate correlation between log plasma A and SBP (r = 0.53), DBP (r = 0.59) and pulse rate (r = 0.41). In keeping with previously published work in younger subjects these results indicate a possible role for adrenaline in the maintenance of raised blood pressure levels in elderly people.

Aged↗
PubMed1993

Reproducibility of ambulatory and clinic blood pressure measurements in elderly hypertensive subjects.

OBJECTIVES: To compare the reproducibility of clinic and ambulatory blood pressure measurements in elderly hypertensive subjects. SUBJECTS: Twenty-two untreated elderly hypertensives, with a clinic systolic blood pressure (SBP) > 160 mmHg and/or diastolic blood pressure (DBP) > 95 mmHg, and a mean age of 76 years (range 66-86). METHODS: Following three supine clinic blood pressure readings the subjects underwent 24-h non-invasive ambulatory blood pressure monitoring, measurements being taken at 20-min intervals from 0700 to 2200 h and at 30-min intervals from 2200 to 0700 h. Measurements were repeated during a further visit at a median interval of 10 weeks (range 1-10 months). RESULTS: Daytime ambulatory SBP levels were 20 mmHg (95% confidence interval 14-27 mmHg, P < 0.001) lower than clinic SBP, although DBP values were similar. The mean 24-h ambulatory SBP and DBP reproducibility [assessed by the standard deviation of differences (SDD) between visits] was significantly better than that for mean clinic blood pressure (SBP 6.3 versus 17.4 mmHg, P < 0.001; DBP 4.8 versus 7.0 mmHg, respectively, P < 0.05). With daytime defined as 1000-1959 h, the SDD between visits was 12.4 mmHg for SBP and 8.3 mmHg for DBP, but with daytime defined as 0700-2159 h, the SDD fell to 6.0 mmHg for SBP and 4.8 mmHg for DBP, values almost identical to those obtained with full 24-h blood pressure monitoring. There was no difference in night-time blood pressure reproducibility, whether night-time was defined as 2400-0559 h or 2200-0659 h. CONCLUSIONS: Both 24-h and daytime ambulatory blood pressure monitoring significantly improve the reproducibility of blood pressure measurements compared with clinic blood pressure readings in elderly hypertensive subjects. Increasing the number of daytime blood pressure readings by 50% (from 30 to 45) reduced the variability of blood pressure measurement by 50%. Twenty-four-hour ambulatory blood pressure monitoring is of value in obtaining reproducible blood pressure measurements in elderly hypertensive subjects. However, more than 30 readings are needed during a daytime recording to significantly reduce variability compared with repeated clinic measurements, although night-time variability is not significantly affected if the number of readings is reduced to 12 over a 6-h period.

Age Factors↗
PubMed1993

Effects of moderate sodium restriction on clinic and twenty-four-hour ambulatory blood pressure in elderly hypertensive subjects.

OBJECTIVE: To assess the effects of 80 mmol/day reduction in dietary sodium intake on clinic and 24-h ambulatory blood pressure in elderly hypertensive subjects. DESIGN: Double-blind, randomized, placebo-controlled, crossover trial lasting 10 weeks, following a 4-week run-in period. SUBJECTS: Seventeen untreated subjects with essential hypertension [systolic blood pressure (SBP) > or = 160 mmHg and/or diastolic blood pressure (DBP) > or = 95 mmHg], mean age 73 years (range 66-79). INTERVENTIONS: Subjects had clinic blood pressure and 24-h urinary electrolyte excretion measured while on their normal diet. Following a 4-week run-in period on a reduced-sodium diet (80-100 mmol/24 h) subjects entered a 10-week crossover trial of 80 mmol/24 h sodium supplement or matching placebo while continuing on the reduced-sodium diet. MAIN OUTCOME MEASURES: The within-patient change in clinic and 24-h ambulatory blood pressures at the end of each intervention period. RESULTS: Mean urinary sodium excretion at the end of the run-in phase rose during the high sodium intake phase and was reduced significantly at the end of the low sodium intake phase. There was a significant reduction in clinic supine SBP between the high- and low-sodium phases. There was no significant change in standing SBP, supine or standing DBP or pulse rate between phases. There was a non-significant reduction in mean 24-h SBP and DBP on the low sodium intake. At the end of the low-sodium phase there was a significant increase in plasma renin activity and aldosterone levels, but no change in plasma electrolytes. CONCLUSIONS: Overall, moderate sodium restriction in elderly hypertensives resulted in a significant fall in clinic supine SBP only, although marked differences in intersubject responses were found. Moderate sodium restriction may be of benefit in only some elderly hypertensive subjects as part of a non-pharmacological regimen for blood pressure reduction.

Aged↗
PubMed1993

Age-related differences in simultaneous interarm blood pressure measurements.

Simultaneous noninvasive blood pressure measurement were recorded bilaterally in 40 young and 40 elderly subjects. Overall interarm blood pressure (BP) differences for the elderly and young groups were similar, the absolute interarm differences being for systolic blood pressure (SBP) elderly: 4.2 mmHg (95% CI 3.1-5.3 mmHg); young 3.3 mmHg(2.6-4.1 mmHg); diastolic blood pressure (DBP) elderly 3.6 mmHg(2.8-4.4 mmHg), young 2.7 mmHg(2.0-3.3 mmHg). However, the range of interarm BP differences was wide. Four (10%) of the elderly had an interarm SBP difference > 10 mmHg compared to one (3%) of the young group. Interarm DBP differences > 8 mmHg were found in three (8%) of the elderly and in none of the young group. Although age does not affect mean interarm BP differences, clinically important interarm BP differences exist in both young and elderly subjects. Blood pressure should be measured in both arms of all patients at initial assessment to avoid potential problems with misclassification of blood pressure status.

Adult↗