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Laboratory monitoring and adverse patient outcomes with antihypertensive therapy in primary care
Author(s) -
McDowell Sarah E.,
Coleman Jamie J.,
Evans Stephen J. W.,
Gill Paramjit S.,
Ferner R. E.
Publication year - 2010
Publication title -
pharmacoepidemiology and drug safety
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.023
H-Index - 96
eISSN - 1099-1557
pISSN - 1053-8569
DOI - 10.1002/pds.1935
Subject(s) - medicine , adverse effect , creatinine , hazard ratio , retrospective cohort study , emergency medicine , pediatrics , confidence interval
Purpose The monitoring of serum electrolyte and creatinine concentrations in patients treated with antihypertensive therapy is recommended. We wished to examine the relationship between laboratory monitoring and adverse patient outcomes. Methods We carried out a retrospective cohort study using the General Practice Research Database (GPRD). Patients aged 18 years or older with newly diagnosed hypertension and prescribed a single antihypertensive agent were included. Monitoring was defined as any laboratory test for serum electrolyte and creatinine (or urea) concentrations within 6 months of starting treatment. Results We identified 74 096 patients who were newly diagnosed with hypertension and prescribed a single antihypertensive agent. Twenty six thousand nine hundred forty six (36.4%) patients had any biochemical laboratory measurement within 6 months. Three hundred ten patients (0.4%) died, 1451 (2%) were admitted to hospital at least once and 29 749 (40.2%) discontinued their first course of antihypertensive treatment within 6 months. Patients were more likely to be admitted to hospital if their biochemistry had been monitored after beginning treatment (adjusted hazard ratio (HR) 1.37; 95%CI 1.21–1.55). They were also marginally more likely to discontinue treatment (adjusted HR 1.04; 95%CI 1.02–1.07). They were not significantly more likely to die (adjusted HR 1.21; 95%CI 0.87–1.67). Conclusions Biochemical testing at baseline and monitoring after starting treatment is often omitted in newly diagnosed hypertensive patients. Those patients who are monitored are more likely to be admitted to hospital and to discontinue initial antihypertensive therapy, but not to die. Many biochemical adverse drug reactions are found only by laboratory monitoring. Copyright © 2010 John Wiley & Sons, Ltd.