Oversight: a retrospective study of biochemical monitoring in patients beginning antihypertensive drug treatment in primary care

Abstract

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT • Guidelines recommend biochemical monitoring of patients treated with antihypertensive agents, although there is little primary evidence for these recommendations. WHAT THIS STUDY ADDS • Patients treated for hypertension in general practice often have no biochemical tests before, or in the 6 months after, starting drug treatment. AIMS Guidelines on the management of hypertension have recommended baseline testing of serum electrolyte and creatinine concentrations before treatment since the 1990s. We wished to examine the extent of laboratory monitoring in patients with newly diagnosed hypertension and newly treated with antihypertensive drugs. METHODS We carried out a retrospective analysis of 74 096 patients in the General Practice Research Database (GPRD) aged 18 years and older with newly diagnosed hypertension and prescribed a single antihypertensive agent. We determined the number of patients with a laboratory test for serum electrolyte and creatinine (or urea) concentrations prior to the first antihypertensive drug prescription and in the 6 months after and patient factors associated with subsequent monitoring. RESULTS Thirty‐four thousand nine hundred and forty‐seven patients (47%) had at least one biochemical test in the 12 months prior to beginning antihypertensive treatment, and 26 946 (36%) had at least one biochemical monitoring test in the 6 months after beginning antihypertensive treatment. Thirteen thousand five hundred and four (18%) had both baseline and monitoring tests. Baseline tests were normal in 11 671 patients (86%), of whom 10 213 (88%) had normal tests at first monitoring. Monitoring was significantly more likely in patients treated with ACE inhibitors than thiazides (adjusted OR 1.90; 95% CI 1.80, 2.00), older patients (adjusted OR 1.23; 95% CI 1.11, 1.36) [individuals aged 80–89 years compared with <40 years], and patients with diabetes mellitus (adjusted OR 2.03; 95% CI 1.91, 2.16). CONCLUSION Biochemical testing at baseline and monitoring after starting treatment is often omitted in newly diagnosed hypertensive patients. When both are tested, one in eight normal results becomes abnormal.

Adherence to guidelines for creatinine and potassium monitoring and discontinuation following renin–angiotensin system blockade: a UK general practice-based cohort study

“…26 30 Consistent with some,26 30 but not all, previous studies,28 we found no association for diabetes. However, these previous studies reporting an association for diabetes focused on monitoring within broader intervals ( eg, 6 months),28 where patients with diabetes, irrespective of ACEI/ARB initiation, were likely to receive blood testing owing to the diabetes QOF programme.…”

“…Only one previous study19 examined monitoring according to guideline-recommended intervals (<14 days). All others have used longer intervals ( eg, 30 days26 or 6 months27 28), which make interpretations and implications for clinical practice less clear. Poor adherence to monitoring guidelines after ACEI/ARB initiation is not restricted to the UK,19 28 29 but has also been reported in the USA,30–32 Canada33 and the Netherlands 26…”

Influence of Coadministration of Antithrombotic Medicines, Warfarin, and NSAIDs on Heparin Safety: Data from a Prospective Observational Study

“…The comprehensive list of indications for this pharmaceutical category illustrates how frequently these drugs are used in daily medical practice. 8,9 Worldwide heparin utilization trends have shown 10% to 15% yearly growth in the past decade. These medicines were primarily used in the inpatient setting, and heparins consumed up to 10% of the total medication costs in hospitals.…”

An agenda for UK clinical pharmacology: Pharmacoepidemiology

“…In the more general population the benefits of diagnostic test monitoring are not known with confidence, and it occupies a great deal of resources in practice [29], but further research in this area is also required.…”