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Biomedical subjects

T M MacDonald

Publications and source records attributed to T M MacDonald.

At least 73 records · Page 4Linked to original sources
PubMed2000

Impact of type 1 and type 2 diabetes on patterns and costs of drug prescribing: a population-based study.

OBJECTIVE: Utilization and costs of prescription drugs were investigated in diabetic and nondiabetic patients. RESEARCH DESIGN AND METHODS: The study was carried out in Tayside, Scotland, U.K. A validated population-based diabetes register was used to identify patients with type 1 and type 2 diabetes, and a database of all prescriptions dispensed in the community was used to investigate drug utilization in 1995. RESULTS: In a population of 406,526, there were 974 (0.2%) with type 1 diabetes and 6,869 (1.7%) with type 2 diabetes. The mean dispensed prescribing rates for all drugs (excluding antidiabetic medication) were higher across all age-groups for diabetic patients. After adjusting for age, patients with type 1 diabetes were 2.07 times (95% CI 2.03-2.11) more likely and patients with type 2 diabetes were 1.70 times (1.69-1.71) more likely to be dispensed a drug item than people without diabetes. This likelihood was increased in every drug category, even those not directly related to diabetes, and the proportion and cost of drug items dispensed to diabetic patients was therefore higher than expected given the prevalence of diabetes. Upon projecting these results to the U.K. population, it was discovered that nearly 8% of the U.K. drug budget (Pound Sterling 350 million) is accounted for by patients with diabetes (90% of that by patients with type 2 diabetes). CONCLUSIONS: This study highlights the increased usage and cost of prescription drugs in diabetes, with type 2 diabetes constituting a particular burden. It was discovered that 1.4% of drug usage in the entire population can be accounted for by the increased prescribing rate of diabetic patients compared with that of nondiabetic patients.

Adolescent↗
PubMed2000

Socio-economic status, obesity and prevalence of Type 1 and Type 2 diabetes mellitus.

AIMS: The influence of socio-economic status on the prevalence of Type 1 and Type 2 diabetes mellitus, and on obesity, was explored using routinely collected healthcare data for the population of Tayside, Scotland. METHODS: Among 366,849 Tayside residents, 792 and 5,474 patients with Type 1 and Type 2 diabetes, respectively, were identified from a diabetes register. The Carstairs Score was used as a proxy for socio-economic status. This is a material deprivation measure derived from the UK census, using postcode data for four key variables. Odds ratios for diabetes prevalence, adjusted for age, were determined for each of six deprivation categories (1 - least deprived, 6/7 - most deprived). The mean body mass index (BMI) in each group was also determined, and the effect of deprivation category explored by analysis of covariance, adjusting for age and sex. RESULTS: The prevalence of Type 2 diabetes, but not Type 1 diabetes, varied by deprivation. People in deprivation category 6 and 7 were 1.6-times (95% confidence interval 1.4-1.8) more likely to have Type 2 diabetes than those least deprived. There was no relationship between deprivation and BMI in Type 1 diabetes (P = 0.36), but there was an increase in BMI with increasing deprivation in Type 2 diabetes (P < 0.001; test of linearity P < 0.001). CONCLUSIONS: The study confirms the relationship between deprivation and the prevalence of Type 2 diabetes. There are more obese, diabetic patients in deprived areas. They require more targeted resources and more primary prevention.

Adult↗
PubMed1999

Frequency of blood glucose monitoring in relation to glycaemic control: observational study with diabetes database.

OBJECTIVES: To investigate patterns of self monitoring of blood glucose concentration in diabetic patients who use insulin and to determine whether frequency of self monitoring is related to glycaemic control. SETTING: Diabetes database, Tayside, Scotland. SUBJECTS: Patients resident in Tayside in 1993-5 who were using insulin and were registered on the database and diagnosed with insulin dependent (type 1) or non-insulin dependent (type 2) diabetes before 1993. MAIN OUTCOME MEASURES: Number of glucose monitoring reagent strips dispensed (reagent strip uptake) derived from records of prescriptions. First recorded haemoglobin A1c concentration in the study period, and reagent strips dispensed in the previous 6 months. RESULTS: Among 807 patients with type 1 diabetes, 128 (16%) did not redeem any prescriptions for glucose monitoring reagent strips in the 3 year study period. Only 161 (20%) redeemed prescriptions for enough reagent strips to test glucose daily. The corresponding figures for the 790 patients with type 2 diabetes who used insulin were 162 (21%; no strips) and 131 (17%; daily tests). Reagent strip uptake was influenced both by age and by deprivation category. There was a direct relation between uptake and glycaemic control for 258 patients (with recorded haemoglobin A1c concentrations) with type 1 diabetes. In a linear regression model the decrease in haemoglobin A1c concentration for every extra 180 reagent strips dispensed was 0.7%. For the 290 patients with type 2 diabetes who used insulin there was no such relation. CONCLUSIONS: Self monitoring of blood glucose concentration is associated with improved glycaemic control in patients with type 1 diabetes. Regular self monitoring in patients with type 1 and type 2 diabetes is uncommon.

Age Factors↗
PubMed1999

Oral contraceptives and myocardial infarction: results of the MICA case-control study.

OBJECTIVES: To determine the association between myocardial infarction and use of different types of oral contraception in young women. DESIGN: Community based case-control study. Data from interviews and general practice records. SETTING: England, Scotland, and Wales. PARTICIPANTS: Cases (n=448) were recruited from women aged between 16 and 44 who had suffered an incident myocardial infarction between 1 October 1993 and 16 October 1995. Controls (n=1728) were women without a diagnosis of myocardial infarction matched for age and general practice. MAIN OUTCOME MEASURES: Odds ratios for myocardial infarction in current users of all combined oral contraceptives stratified by their progestagen content compared with non-users; current users of third generation versus second generation oral contraceptives. RESULTS: The adjusted odds ratio for myocardial infarction was 1.40 (95% confidence interval 0.78 to 2. 52) for all combined oral contraceptive users, 1.10 (0.52 to 2.30) for second generation users, and 1.96 (0.87 to 4.39) for third generation users. Subgroup analysis by progestagen content did not show any significant difference from 1, and there was no effect of duration of use. The adjusted odds ratio for third generation users versus second generation users was 1.78 (0.66 to 4.83). 87% of cases were not exposed to an oral contraceptive, and 88% had clinical cardiovascular risk factors or were smokers, or both. Smoking was strongly associated with myocardial infarction: adjusted odds ratio 12.5 (7.29 to 21.5) for smoking 20 or more cigarettes a day. CONCLUSIONS: There was no significant association between the use of oral contraceptives and myocardial infarction. The modest and non-significant point estimates for this association have wide confidence intervals. There was no significant difference between second and third generation products.

Adolescent↗
PubMed1999

The effect of hip replacement on prescribing of NSAIDs, ulcer healing drugs and hospitalization--a matched cohort study.

PURPOSE: To assess the impact of total hip replacement on prescribing of non-steroidal anti-inflammatory drugs (NSAIDs), ulcer healing drugs (UHDs) and hospitalization. METHODS: Observational matched cohort study. RESULTS: There were 282 subjects in the hip replacement cohort and 1691 in the comparator cohort. Dispensing of NSAIDs fell from 89% to 57% after hip replacement but increased from 36% to 39% in comparators. Dispensing of UHDs fell from 33% to 30% after hip replacement but increased from 16% to 23% in the comparators. Hospitalization for upper gastrointestinal events fell from 2.5% to 1.8% after hip replacement but increased from 1.4% to 1.7% in comparators. Hospitalization for other causes increased from 32% to 42% after hip replacement compared with 25% to 28% in comparators. CONCLUSIONS: Hip replacement is associated with reduced prescribing of NSAIDs and UHDs. However, any effect on GI admissions will be small compared with increased hospitalization for other causes.

Journal Article↗
PubMed1999

Prescription of acid-suppressing drugs in relation to endoscopic diagnosis: a record-linkage study.

BACKGROUND: Although widely used, few data are available on the appropriateness of prescribing of acid-suppressing drugs (ASDs), despite guidelines on the investigation and treatment of dyspeptic patients. METHODS: We created a database of 62 000 endoscopy examinations and record-linked these to a prescribing database. Endoscopic diagnoses were classified into peptic, nonpeptic and others. The H2-antagonists, omeprazole and misoprostol, were studied. RESULTS: 35 000 patients had one or more endoscopies during 1978-93; two-thirds were over 45 years of age at first endoscopy. A quarter of all patients who had been endoscoped had consistently normal examinations. Peptic oesophageal pathology was the commonest positive finding. A quarter of those prescribed ASDs between 1989 and 1993 had been endoscoped between 1978 and 1993. In those with a peptic diagnosis prescribed any ASD, the pathologies found were: oesophageal (42.9%), duodenal (36.3%) and gastro-pyloric (21.3%). Patients prescribed omeprazole were more likely to have undergone endoscopy than those prescribed other ASDs, and they were also more likely to have peptic oesophageal pathology. Long-term prescribing (>56 days per year) occurred in two-thirds of patients prescribed ASDs and 40% had at least one endoscopy. In those prescribed short-term ASDs, 20% had undergone at least one endoscopy. Peptic and nonpeptic endoscopic pathology was associated with increased ASD prescribing, but a normal endoscopy did not reduce prescribing. CONCLUSION: ASD prescribing appeared to be mainly symptom-driven. Positive endoscopic findings increased the prescribing of ASDs, but normal findings did not reduce it.

Aged↗
PubMed1999

Raised aldosterone to renin ratio predicts antihypertensive efficacy of spironolactone: a prospective cohort follow-up study.

AIMS: Aldosterone/renin ratio is an index for inappropriate aldosterone activity, and it is increasingly being used to screen for primary aldosteronism within the hypertensive population. It may also be a good index to help predict the response to spironolactone. To assess the blood pressure response to oral spironolactone in hypertensive patients with primary aldosteronism identified with raised aldosterone to renin ratio. METHODS: We conducted a prospective cohort study of hypertensive patients with raised aldosterone/renin ratio, who failed to suppress plasma aldosterone with salt loading and fludrocortisone suppression test. These patients were treated with spironolactone and were followed-up for a period of up to 3 years. RESULTS: We studied 28 (12 male) subjects with a mean age of 55 (s.d. 10) years who were followed up for a mean period of 12.9 (7) months. At baseline, the patients were taking a mean of 2.1 (1.2) antihypertensive drugs, but despite this 16/28 (57%) had diastolic BP >90 mmHg, 39% with systolic BP >160 mmHg. After commencing spironolactone, three patients complained of breast tenderness but continued treatment and one patient was intolerant of spironolactone and had to stop treatment. Of the remaining 27 patients, the mean number of antihypertensive drugs used dropped to spironolactone plus 0.7 (s.d. 0.9). All but one patient (96%) achieved a diastolic BP</=90 mmHg and 78% achieved a systolic BP</=160 mmHg. In total 48% had BP</=140/90 mmHg and 13/27 (48%) were treated with spironolactone monotherapy. Assessing only patients on drug treatment at baseline (n=24), spironolactone significantly reduced the need for antihypertensive drugs by -0.5 (CI 0.1-1.0), P=0.02, as well as reducing blood pressure [systolic BP -15 mmHg (CI 5-25), P=0.007 and diastolic BP (mmHg) by -8 mmHg (CI 4-13), P=0.001]. CONCLUSIONS: Spironolactone was a highly effective antihypertensive agent in hypertensive patients who had a raised aldosterone/renin ratio. As a raised ratio was highly predictive of nonsuppression of plasma aldosterone suggesting primary aldosteronism, it might be worthwhile using spironolactone in this subgroup of hypertensive patients with raised aldosterone/renin ratios, provided that adrenal adenomas are excluded with imaging techniques.

Aldosterone↗
PubMed1999

Record-linkage for pharmacovigilance in Scotland.

Record-linkage is the linkage of patient-specific information that is stored separately. Recent advances in computerization have meant that record-linkage techniques in medical research are increasingly being used and refined. In particular, they have made a significant contribution to pharmacovigilance, which involves linking drug exposure to outcomes data. In this article, the contribution of record-linkage in Scotland to medical research is described. The two organizations that utilize record-linkage techniques are the Medicines Monitoring Unit (MEMO) of the University of Dundee and the Information and Statistics Division (ISD) of the NHS in Scotland. Pharmacovigilance is MEMO's main concern (using data from the Tayside region of Scotland), while ISD link health care datasets for Scotland for general health care research. The experience of the two groups is now being combined to carry out drug safety studies in the entire population of Scotland.

Drug Monitoring↗
PubMed1999

Factors associated with trimethoprim-resistant bacteria isolated from urine samples.

Urine samples with trimethoprim-resistant or trimethoprim-sensitive Gram-negative bacteria and samples with no bacterial growth (NG) were identified. Age-sex matched community controls were generated with each trimethoprim-resistant case. These four groups were evaluated for exposure. Prior trimethoprim use was significantly more common in the trimethoprim-resistant group when compared with the trimethoprim-sensitive or the NG group. Prior hospitalization was significantly less common in the trimethoprim-resistant than the trimethoprim-sensitive group, but not with the NG group. Prior oestrogen exposure was associated with trimethoprim resistance. There were no associations found for diabetes or prior corticosteroid exposure. Community controls were found to be inappropriate controls for the study of trimethoprim-resistant bacteria in urine samples.

Anti-Bacterial Agents↗
PubMed1999

Risk of myocardial infarction in young female smokers.

OBJECTIVES: To determine the extent of risk of myocardial infarction from cigarette smoking in young women, and to examine the relation of smoking with other putative risk factors. DESIGN: Community based case control study. SETTING: England, Scotland, and Wales. PATIENTS: Women (n = 448) between 16 and 44 years old with a diagnosis of incident myocardial infarction between 1 October 1993 and 16 October 1995. Controls (n = 1728) were age and general practice matched women without a diagnosis of myocardial infarction. OUTCOMES MEASURES: Odds ratios for risk of myocardial infarction associated with smoking and other risk factors. RESULTS: Odds ratios for myocardial infarction in smokers versus non-smokers showed a strong dose response, from 2.47 (95% confidence interval (CI) 1.12 to 5.45) in smokers of 1-5 cigarettes per day to 74.6 (95% CI 33.0 to 169) in smokers of >/= 40 cigarettes per day. There was no interaction of smoking with use of oral contraceptives, but there were additive risks with other clinical risk factors such as hypertension and diabetes. It is estimated that if all women aged 16-44 years were able to stop smoking, 400 cases of myocardial infarction per annum (of whom 112 would die) would be prevented. CONCLUSIONS: In young women the risk of myocardial infarction from smoking was considerable, and heavy smokers with other risk factors were especially at risk.

Adolescent↗
PubMed1999

Non-adherence with ACE inhibitor treatment is common in heart failure and can be detected by routine serum ACE activity assays.

OBJECTIVE: To assess whether serum angiotensin converting enzyme (ACE) activity during routine clinical practice accurately reflects patient adherence to ACE inhibitor treatment for chronic heart failure (CHF). DESIGN: Retrospective assessment of ACE inhibitor adherence and serum ACE activity measurements. SETTING: Teaching hospital outpatient department PATIENTS AND INTERVENTIONS: During 1994-95, serum ACE was measured in 73 CHF patients who were routinely attending the heart failure clinic at Ninewells Hospital. At the same time, the medicines monitoring unit collected data on whether and when prescriptions for ACE inhibitors were redeemed at community pharmacies, which enabled each patient's adherence over a prolonged period to be assessed. MAIN OUTCOME MEASURES: Routine collected serum ACE measurements were correlated with measured adherence with ACE inhibitor treatment. RESULTS: In total, 18% of CHF patients appeared to exhibit < 70% adherence with their ACE inhibitor treatment with 34% exhibiting less than 85% adherence and 58% exhibiting < 100% adherence. A serum ACE activity of > 12 u/l gave 91% positive predictive accuracy that the patient was < 100% adherent with their ACE inhibitor treatment. At the other extreme, a serum ACE < 6.5 u/l gave 81% positive predictive accuracy that the patient was > 85% adherent with ACE inhibitor treatment. CONCLUSIONS: Non-adherence with ACE inhibitor treatment was found to be common in patients with CHF. The simple, inexpensive test of serum ACE activity can be used in CHF patients to identify many, although not all, non-adherent patients so that adherence enhancing strategies can be targeted towards them. Further work is clearly required to explore the precise clinical use of this promising test.

Aged↗
PubMed1999

Irbesartan reduces QT dispersion in hypertensive individuals.

Angiotensin type 1 receptor antagonists have direct effects on the autonomic nervous system and myocardium. Because of this, we hypothesized that irbesartan would reduce QT dispersion to a greater degree than amlodipine, a highly selective vasodilator. To test this, we gathered electrocardiographic (ECG) data from a multinational, multicenter, randomized, double-blind parallel group study that compared the antihypertensive efficacy of irbesartan and amlodipine in elderly subjects with mild to moderate hypertension. Subjects were treated for 6 months with either drug. Hydrochlorothiazide and atenolol were added after 12 weeks if blood pressure (BP) remained uncontrolled. ECGs were obtained before randomization and at 6 months. A total of 188 subjects (118 with baseline ECGs) were randomized. We analyzed 104 subjects who had complete ECGs at baseline and after 6 months of treatment. Baseline characteristics between treatments were similar, apart from a slight imbalance in diastolic BP (irbesartan [n=53] versus amlodipine [n=51], 99.2 [SD 3. 6] versus 100.8 [3.8] mm Hg; P=0.03). There were no significant differences in BP normalization (diastolic BP <90 mm Hg) between treatments at 6 months (irbesartan versus amlodipine, 80% versus 88%; P=0.378). We found a significant reduction in QT indexes in the irbesartan group (QTc dispersion mean, -11.4 [34.5] milliseconds, P=0.02; QTc max, -12.8 [35.5] milliseconds, P=0.01), and QTc dispersion did not correlate with the change in BP. The reduction in QT indexes with amlodipine (QTc dispersion, -9.7 [35.4] milliseconds, P=0.06; QTc max, -8.6 [33.2] milliseconds, P=0.07) did not quite reach statistical significance, but there was a correlation between the change in QT indexes and changes in systolic BP. In conclusion, irbesartan improved QT dispersion, and this effect may be important in preventing sudden cardiac death in at-risk hypertensive subjects.

Aged↗
PubMed1999

Costs associated with symptomatic systolic heart failure.

OBJECTIVE: To investigate whether the extent of systolic dysfunction is a useful predictor of the costs of healthcare and social support for patients with heart failure. DESIGN: Cross-sectional study with collection of cost data attributed to management of heart failure in the previous year. SETTING: Four primary-care practices in Scotland. PATIENTS: Patients receiving long term therapy with loop diuretics for suspected heart failure. INTERVENTIONS: Two-dimensional and Doppler echocardiography. MAIN OUTCOME MEASURES AND RESULTS: Two hypotheses were tested: (i) the proportion of patients incurring costs is higher in patients with abnormal left ventricular (LV) function; and (ii) the median cost per patient that incurs costs is higher in patients with abnormal LV function. Of the 226 patients in the study, 67 (30%) had abnormal systolic function. In comparison with the remaining 159 patients, they had higher healthcare costs [560 Pounds vs 440 Pounds per patient year (1994/1995 values)], were more likely to incur hospital inpatient or outpatient costs [Odds ratio (OR): 2.02; 95% confidence interval (CI): 1.06 to 3.84] and had significantly higher primary-care costs (mean 292 Pounds vs 231 Pounds per patient year; p = 0.02, Mann Whitney test). In contrast, they were no more likely to incur social support costs (OR: 1.22; 95% CI: 0.52 to 2.86) and the mean cost of social support per patient year was lower (234 Pounds vs 373 Pounds). CONCLUSIONS: Patients with objectively measured systolic dysfunction incurred significantly higher healthcare costs in the year before diagnosis. This suggests that treatment that improves systolic function will reduce healthcare costs, even in a primary-care population with relatively mild congestive heart failure.

Cross-Sectional Studies↗
PubMed1999

The doctor-patient relationship and prescribing patterns. A view from primary care.

The doctor-patient relationship has been described in economic terms as an 'agency relationship' where informed agents make decisions for uninformed clients. However, the decision to prescribe and the decision to accept the prescription by the patient are more complex in nature and involve many variables. Other factors, such as the 'need' for the prescription and the disease state (acute or chronic) also influence prescribing practice. Communication between the physician and patient was found to be important for rational and effective prescribing. The client can make better decisions with the relevant information, thus breaking down the agency relationship that once existed.

Drug Prescriptions↗
PubMed1998

Association of road-traffic accidents with benzodiazepine use.

BACKGROUND: Psychomotor studies suggest that commonly prescribed psychoactive drugs impair driving skills. We have examined the association between the use of psychoactive drugs and road-traffic accidents. METHODS: We used dispensed prescribing as a measure of exposure in a within-person case-crossover study of drivers aged 18 years and over, resident in Tayside, UK, who experienced a first road-traffic accident between Aug 1, 1992, and June 30, 1995, and had used a psychoactive drug (tricyclic antidepressant, benzodiazepine, selective serotonin-reuptake inhibitor, or other psychoactive drug [mainly major tranquillisers]) between Aug 1, 1992, and the date of the accident. For each driver, the risks of having a road-traffic accident while exposed and not exposed to a drug were compared. FINDINGS: 19386 drivers were involved in a first road-traffic accident during the study period. 1731 were users of any study drug. On the day of the accident, 189 individuals were taking tricyclic antidepressants (within-patient exposure odds ratio for an accident 0.93 [95% CI 0.72-1.21]), 84 selective serotonin-reuptake inhibitors (0.85 [0.55-1.33]), 235 benzodiazepines (1.62 [1.24-2.12]), and 47 other psychoactive drugs (0.88 [0.62-1.25]). The risk associated with benzodiazepine use decreased with increasing driver's age and was greater when the breath test for alcohol was positive. A dose-response relation was evident with benzodiazepines. The increased risk with benzodiazepines was significant for long-half-life drugs, used as anxiolytics, and for short-half-life hypnotics (all zopiclone). INTERPRETATION: Users of anxiolytic benzodiazepines and zopiclone were at increased risk of experiencing a road-traffic accident. Users of anxiolytic benzodiazepines and zopiclone should be advised not to drive.

Accidents, Traffic↗