Sex differences in the medication choice for hypertension in general practice. A study with written case simulations.

The objective of this study was to explore explanations for the preference of physicians to prescribe beta-blockers to hypertensive men and diuretics to hypertensive women. A qualitative study among 12 family physicians was conducted with a combination of written case simulations, semi-structured interviews and statements on attitudes of physicians towards antihypertensive drug choice. Among the male hypertensive cases the most frequently prescribed drugs were beta-blockers, whereas among the female hypertensive cases diuretics were more often prescribed. Physician characteristics associated with a preferred prescribing of beta-blockers to hypertensive men and diuretics to hypertensive women were: older age (no residency in family medicine), the believe that beta-blockers are more effective in men with regard to lowering blood pressure and that diuretics are more effective in women, a non-evidence based attitude and a sex-related attitude towards the choice of beta-blockers and diuretics in general, and in particular towards the prescribing of beta-blockers to hypertensive men because men have a higher absolute risk of coronary heart disease than women. An additional explanation for these findings may be the higher prevalence of ankle oedema among women. Patient characteristics associated with more prescribing of beta-blockers to hypertensive men and diuretics to hypertensive women were: current employment and a "high-risk" profile in terms of blood pressure level and additional cardiovascular risk factors. Although, most considerations underlying a preferred prescribing of beta-blockers to hypertensive men and diuretics to hypertensive women were not evidence-based, the actual choice of antihypertensive drug (diuretic or beta-blocker) was evidence-based. These considerations may also play a role in the sex difference in the choice of calcium antagonists and angiotensin converting enzyme inhibitors and require further investigation.

Estimating the prevalence of hypertension corrected for the effect of within-person variability in blood pressure.

The objective of our study was to assess the applicability of using estimates of within-person variance (WPV) from reproducibility studies for a correction of blood pressure values in another study to improve the accuracy of the prevalence estimation of hypertension. Data were collected from two cross-sectional population-based studies on cardiovascular disease risk factors conducted from 1987 to 1995 among 55,026 subjects aged 20-59 years. Correction factors were calculated from a reproducibility study among 924 subjects who were examined in 1989 and 1990. All other studies with repeated measurements of blood pressure were searched in MEDLINE from 1966 onward. Six studies satisfied the inclusion criteria. The prevalence of hypertension, uncorrected and corrected with factors from other studies, were compared with the prevalence of hypertension corrected with the factor from our study. The uncorrected prevalence of hypertension was 17.3% [95%CI:17.0-17.7]. The prevalence of hypertension after correction for WPV with the factor from our study was 13.5% [95%CI:13.2-13.8]. Correction for WPV with factors from the appropriate studies (depending on factors such as number of measurements taken per visit, and time interval between visits) resulted in prevalences ranging from 13.9% to 14.7%. The bias that occurs when no correction for WPV is performed is much larger (29% overestimation) than the bias that occurs when correction factors are derived from other studies (3.1-8.4% overestimation). When repeated measurements of blood pressure are not available in a population study for a sample of that same study, it is advisable to use data from another study to correct for WPV.

Influence of question structure on the recall of self-reported drug use.

Epidemiological studies often rely on self-reported information as a source of drug exposure. Several studies have evaluated the accuracy of self-reported information on drug use. The influence of question structure on the accuracy of recall, however, has not been studied extensively in these studies. In this study we examined the recall accuracy of questionnaire information on drug use in a ongoing public health survey with special attention to the influence of question structure on sensitivity of recall. A sample of 372 hypertensive subjects for whom questionnaire information and pharmacy records were available was examined. Self-reported information on drug use was obtained through questions about medications used for a specific condition and one final open-ended question. This information was compared with the pharmacy medication history. About 71% of all drugs that were currently in use according to the pharmacy records were recalled through the self-administered questionnaire, and 94% of all drugs mentioned in the questionnaire could be traced in the pharmacy records. Recall sensitivity was higher for questions about medications used for a specific indication (88%) than for the open-ended question (41%). The type of drug that was used might have caused part of this difference in recall. We conclude that questionnaire structure might be of influence on the accuracy of recall of self-reported drug use, and more attention should be paid to the structure of questions on drug use.

Influence of correction for within-person variability in blood pressure on the prevalence, awareness, treatment, and control of hypertension.

We assessed the influence of correction for within-person variability (WPV) on the prevalence, awareness, treatment, and control of hypertension. Data were collected from two cross-sectional population-based studies on cardiovascular disease risk factors from 1987 to 1995 among 56,026 subjects aged 20 to 59 years. Correction factors were calculated from an internal reproducibility study among 924 subjects who were examined in 1989 and 1990. The prevalence of hypertension without a correction of blood pressure values for WPV was substantially overestimated (38%), whereas the prevalence of awareness and treatment of hypertension were substantially underestimated (-13% and -28%). The prevalence of control of hypertension did not change much after this correction. It may be advisable to perform a correction for within-person variability to obtain valid prevalence estimates in surveys that only take one or two measurements of blood pressure.

Cardiovascular diseases and risk factors in a population-based study in The Netherlands: agreement between questionnaire information and medical records.

BACKGROUND: Since 1987 the Monitoring Project on Cardiovascular Risk Factors has been carried out in The Netherlands. The purpose of the present study was to assess the agreement between the self-reported questionnaire information that was collected in this survey on cardiovascular diseases and risk factors and information from medical records. METHODS: From 1987 to 1991, over 36,000 men and women aged 20-59 years have participated in the Monitoring Project on Cardiovascular Disease Risk Factors, a cross-sectional population-based study. We compared self-reported information on cardiovascular diseases and risk factors with the general practitioners medical records from a sample of 899 hypertensive subjects. RESULTS: The highest proportion of positive self-reports could be confirmed by the medical records for diabetes conditional on self-report of medication use for this condition (100%), and a history of hypertension conditional on the presence of blood pressure recordings in the medical records (91%). The lowest percentage of positive self-reports confirmed by medical records was a family history of myocardial infarction (3-5%). More than 80% of the negative self-reports were confirmed by the medical records for most conditions, except for history of hypertension, conditional on the presence of blood pressure recordings in the medical records (40%). The overall agreement above chance was substantial for cerebrovascular disease (kappa = 0.78) and diabetes (kappa = 0.75), moderate for myocardial infarction (kappa = 0.55), poor for myocardial infarction of the respondents' father (kappa = 0.07) and mother (kappa = 0.05), and fair to moderate for all other self-reported conditions. CONCLUSION: Agreement between self-reported information and medical records was variable. For further studies, self-reports of cardiovascular diseases and risk factors should preferably be complemented with information from other sources such as medical records.

Agreement between self-reported antihypertensive drug use and pharmacy records in a population-based study in The Netherlands.

From 1987 to 1991, over 36,000 men and women aged 20-59 years have been examined in the Monitoring Project on Cardiovascular Disease Risk Factors in The Netherlands. Classification of the treatment status of hypertensives in this population-based study was based on self-administered questionnaires. In order to assess the accuracy of self-reported antihypertensive drug use we compared the questionnaire information with computerized pharmacy records from a sample of 372 hypertensive subjects. Most antihypertensive drugs that were mentioned in the questionnaire were present in the pharmacy medication history (93%). However, this percentage was less (76%) when a comparison was made with the calculated duration of use based on the number of units prescribed and the directions for use in the pharmacy records. About 94% of the hypertensive subjects who were using an antihypertensive drug according to the pharmacy records, also mentioned at least one antihypertensive drug in the questionnaire. Agreement between self-reported antihypertensive drug use and pharmacy records was consistently high for all classes of antihypertensive drugs. Among 321 (86%) subjects, the number and types of self-reported antihypertensive drugs were exactly the same as in the pharmacy records. In conclusion, the agreement between self-reported antihypertensive drug use and pharmacy records was high, and the self-reported questionnaire information on antihypertensive drug use can be reliably used for the classification of treatment status of hypertensive subjects in this population-based study.

Excess stroke among hypertensive men and women attributable to undertreatment of hypertension.

BACKGROUND AND PURPOSE: Most population-based studies indicate that a considerable proportion of hypertensive subjects are undertreated and that undertreatment is more prevalent among hypertensive men than among hypertensive women. The aim of our study was to investigate the consequences of undertreatment of hypertension for women and men in terms of stroke occurrence. METHODS: Approximately 45 000 men and women aged >/=20 years were examined in 2 population-based studies in the Netherlands. A cohort of 2616 hypertensive subjects (pharmacologically treated hypertensives and untreated hypertensives who needed pharmacological treatment according to the severity of their hypertension and the coexistence of additional cardiovascular risk factors) was selected for a follow-up study. Follow-up (mean duration, 4.6 years) was complete for 2369 (91%) of the enrolled hypertensive subjects. RESULTS: Compared with treated and controlled hypertensives, the relative risks of stroke for treated and uncontrolled hypertensives and for untreated hypertensives who needed treatment were 1.30 (95% CI, 0.70 to 2.44) and 1.76 (95% CI, 1.05 to 2.94), respectively. These relative risks and the prevalence of (undertreated) hypertension in the total population of 45 000 subjects were used to estimate the number of strokes in the Netherlands attributable to undertreatment. Among hypertensive men and women aged >/=20 years in the Netherlands, the proportions of strokes attributable to treated but uncontrolled blood pressure were 3.1% (95% CI, -5.2% to 18.7%) and 4.1% (95% CI, -7.2% to 20.7%), respectively. For untreated hypertensive men and women who should have been treated, these proportions were 22.8% (95% CI, 0.8% to 38.4%) and 25.4% (95% CI, 0. 5% to 42.5%), respectively. CONCLUSIONS: Increasing the detection of hypertension and improving adherence to current guidelines might prevent a considerable proportion of the incident strokes among hypertensives. The potential impact of achieving control of blood pressure in patients already being treated on the reduction of strokes requires further investigation.

Sex differences in antihypertensive drug use: determinants of the choice of medication for hypertension.

OBJECTIVE: To describe and explain sex differences in antihypertensive drug use. DESIGN AND METHODS: From 1987 to 1995, two cross-sectional population-based surveys of cardiovascular disease risk factors in The Netherlands were carried out among 56026 men and women aged 20-59 years. Polytomous logistic regression modelling was used to adjust for potential confounders of the association between sex and use of different antihypertensive drugs. RESULTS: The response rate was 40% for men and 46% for women. Of these respondents, 40% (1041) of the hypertensive men and 59% (1403) of the hypertensive women were being treated pharmacologically; 57% (595) of the treated men and 54% (760) of the treated women were on monotherapy for hypertension with a diuretic (men 14.8%, women 37.2%), a beta-blocker (men 59.0%, women 45.3%), a calcium antagonist (men 8.6%, women 5.0%) or an angiotensin converting enzyme inhibitor (men 17.7%, women 12.5%). Among those on monotherapy for hypertension, women were less likely than men to be using a beta-blocker [prevalence odds ratio (POR), female/male=0.34; 95% confidence interval (CI) 0.24-0.47], a calcium antagonist (POR=0.27, 95% CI 0.15-0.48) or an angiotensin converting enzyme inhibitor (POR=0.34, 95% CI 0.22-0.52) than a diuretic. These sex differences persisted after adjustment for all factors that could have influenced the choice of these antihypertensive drugs (indications and contra-indications for the four antihypertensive drug classes). The sex differences in antihypertensive drug use were smaller among hypertensives with a history of cardiovascular disease (adjusted PORs, female/male, for beta-blockers, calcium antagonists and ACE inhibitors, respectively, compared to diuretics were 0.80 with 95% CI 0.20-3.24, 0.40 with 95% CI 0.10-0.48 and 0.64 with 95% CI 0.12-3.39) than among those without such a history. CONCLUSIONS: The different patterns of antihypertensive drug use among hypertensive men and women seem irrational, and cannot be explained by factors known to influence antihypertensive drug choice. Among hypertensives with a history of cardiovascular disease, the sex differences were smaller than among those without such a history. Further research is required to explain the sex differences in the choice of antihypertensive drug by prescribers, and to investigate the consequences of these differences for long-term patient outcomes.

Undertreatment of hypertension in a population-based study in The Netherlands.

OBJECTIVE: To estimate the level of undertreatment of hypertension in a population-based study by taking into account the co-existence of additional cardiovascular risk factors in untreated hypertensives, uncontrolled blood pressure among pharmacologically treated hypertensives and within-person variability in blood pressure and total cholesterol. DESIGN: Cross-sectional. SETTING: Two population-based surveys on cardiovascular disease risk factors conducted during 1987-1995 in The Netherlands. PARTICIPANTS: 56 026 men and women aged 20-59 years. MAIN OUTCOME MEASURES: Prevalence of hypertension, of treatment and of undertreatment of hypertension. Undertreated hypertensives were those who were treated pharmacologically, but whose blood pressure was still elevated and those who inappropriately received no medication for the treatment of hypertension. RESULTS: During the past decade in The Netherlands, 30% of the hypertensive women and 47% of the hypertensive men aged 20-59 years were undertreated for hypertension. In both men and women treated pharmacologically, 42 and 29%, respectively, still had elevated blood pressure levels. Of those hypertensive men and women not treated pharmacologically, 53 and 34%, respectively, should have been treated when additional cardiovascular risk factors were taken into account Among those diagnosed but untreated for hypertension, 58 and 31% of the men and women, respectively, should have been treated pharmacologically. CONCLUSION: A considerable proportion of hypertensives were undertreated for hypertension. To decrease the undertreatment of hypertension, it is necessary to obtain better control of blood pressure in patients already being treated, increase the detection of hypertension and improve adherence to the current guidelines.

Measurement of patient compliance.

The compliance of 91 diabetic patients using oral antidiabetics was studied. Patient compliance was measured using four different methods. Patients received their medication in a Medication Event Monitoring System (MEMS)-container. Each time the patient went back to the pharmacy for refill prescriptions, the number of tablets left in the container were counted. Pharmacy records were used to study the number of days of delay in getting the next refill. At the end of the study, a questionnaire was sent to every patient. Using MEMS as a standard, the results show that pill count and refill data overestimate the compliance of this group of patients. The MEMS data also show that the compliance data using only the number of tablets may be biased, because of possible overconsumption. Pill count does not show a correlation with compliance as measured by MEMS. The relation between compliance as measured with MEMS and refill compliance is weak.

Impact of dosage frequency on patient compliance.

OBJECTIVE: To evaluate the impact of dosage frequency on the compliance of patients who receive their medicines from community pharmacies. RESEARCH DESIGN AND METHODS: Each month, patients received a supply of their medication in a Medication Event Monitoring Systems container, which registered each opening of the package. At the end of the study, the patients received a short questionnaire. The subjects were 91 diabetic patients using oral antidiabetic agents. Patients taking insulin and those who were unable to collect their medicines from the pharmacy were excluded from the study. Compliance was defined as the percentage of doses taken during the observation period. Another parameter used was compliance with the prescribed regimen, defined as the percentage of days in which the number of tablets were taken as prescribed. As a last parameter, compliance with the prescribed dose intervals was used. RESULTS: Compliance is influenced by the frequency of doses. The compliance for this group of patients is 74.8%, with an average of 79% in the case of a dose once daily and 38% in the case of a dose three times daily. The predominant type of noncompliance in all groups was dose omissions. However, more than one-third of the patients used more doses than prescribed. Overconsumption is a frequently made mistake by patients on a one-dose daily schedule. CONCLUSIONS: The reduction of dose frequency may decrease total noncompliance, but at the same time, it increases the risk of overconsumption. Reducing the frequency does not automatically result in a better therapeutic schedule. The choice of once or twice daily should depend on the therapeutic range of the drug.

Sex differences in the pharmacological treatment of hypertension: a review of population-based studies.

OBJECTIVE: To summarize all available literature on sex differences in the pharmacological treatment of hypertension with respect to the percentage of hypertensive patients treated pharmacologically and the selection of antihypertensive drugs. The influences of the calendar period, age, definition of hypertension, prevalence of hypertension and country on these sex differences were examined. DATA IDENTIFICATION: A secondary analysis of data from 46 population-based studies in 22 countries on the prevalence of pharmacologically treated hypertension was conducted to estimate sex ratios for the prevalence of drug treatment for hypertension. RESULT: Overall, women with hypertension were 1.33-fold [95% confidence interval (CI) 1.32-1.34] more likely to be treated pharmacologically for hypertension than were hypertensive men. With increasing age, the female: male ratio for pharmacological treatment of hypertension decreased from 2.26 (95% CI 1.56-3.27) at ages 20-29 years to 1.22 (95% CI 1.11-1.34) at ages 60-69 years. In all countries more women than men were treated for hypertension, with the biggest difference observed in the USSR (1983-1986), where about twice as many women as men were treated for hypertension. Women more frequently used diuretics, whereas men more often used beta-blockers, angiotensin converting enzyme inhibitors and calcium antagonists. CONCLUSIONS: Hypertensive women are more often treated for hypertension than hypertensive men and their pattern of use of antihypertensive drugs differs from that of men. Further research is required in order to explain sex differences in the treatment of hypertension with respect to the prevalence of pharmacological treatment of hypertension and choice of antihypertensive drugs, and to investigate the consequences of this difference for long-term outcomes.

Angiotensin converting enzyme inhibitor associated cough: a population-based case-control study.

The objectives of this study were to determine the risk for coughing as an adverse reaction to angiotensin converting enzyme (ACE) inhibitors under everyday circumstances in a large population and to study whether this adverse effect is more common in women. A population-based case-control study was used. The study was set in the practices of 161 Dutch general practitioners (GPs), in which all consultations, morbidity, mortality, medical interventions and prescriptions were registered during 4 consecutive 3-month periods in 4 consecutive groups of 40-41 GPs. The subjects were 2436 patients with incident coughing and up to 3 controls per case were obtained (total group: 7348 controls), matched for GP and a contemporary consultation in the same 3 months. All cases and controls were 20 years or older and had no notification of respiratory infections, influenza, tuberculosis, asthma, chronic bronchitis, emphysema, congestive heart failure, sinusitis, laryngitis, haemoptysis or respiratory neoplasms during the 3-month period. The results showed that cases were 3.6 times as likely as controls to have been exposed to ACE inhibitors (95% CI: 2.4-5.5) but after adjustment for potential confounders the odds ratio was 2.5 (95% CI: 1.6-3.9). The crude odds ratio for males was 2.7 (95% CI: 1.4-5.1) and for females 4.2 (95% CI: 2.4-7.5). The adjusted odds ratio for males was 1.8 (95% CI: 0.9-3.5) and for females 2.7 (95% CI: 1.5-4.8).(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacist-physician co-operation at a regional level.

In the Dutch region of "Betuwe" the hospital pharmacists and community pharmacists together provide short drug letters about new drugs, which are sent bimonthly to all the practising general practitioners (n = 83) and medical specialists (n = 50) in this region. A survey was conducted among these physicians in order to investigate their opinion about and reported use of the drug letters in comparison with other drug-information sources. The majority of the responding physicians (response rate 68%) was found to read the drug letter frequently and evaluated the drug letter as a useful source of information about drugs, especially its section about the advantages and disadvantages of the new drug compared to other drugs. With respect to the different stages of the drug-adoption process, the drug letter was found to be the most frequently used information source at the decision stage. At the introduction stage the pharmaceutical industry representative seems to be the most frequently used source of information, while at the information stage it is the "Geneesmiddelenbulletin" (Drug Bulletin). The majority of the responding general practitioners reported to participate in local group meetings with pharmacists. However, in only 20% of these group meetings attention is given to the drug letter. Since it is known that written information has only a limited influence on the physician's behaviour, the influence of the "Betuwe Circulaire" may increase when attention is paid to it in the local contacts between pharmacists and physicians.