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

What methods are being used to create an evidence base on the use of laboratory tests to monitor long-term conditions in primary care? A scoping review

BACKGROUND

Studies have shown unwarranted variation in test ordering among GP practices and regions, which may lead to patient harm and increased health care costs. There is currently no robust evidence base to inform guidelines on monitoring long-term conditions.

OBJECTIVES

To map the extent and nature of research that provides evidence on the use of laboratory tests to monitor long-term conditions in primary care, and to identify gaps in existing research.

METHODS

We performed a scoping review-a relatively new approach for mapping research evidence across broad topics-using data abstraction forms and charting data according to a scoping framework. We searched CINAHL, EMBASE and MEDLINE to April 2019. We included studies that aimed to optimize the use of laboratory tests and determine costs, patient harm or variation related to testing in a primary care population with long-term conditions.

RESULTS

Ninety-four studies were included. Forty percent aimed to describe variation in test ordering and 36% to investigate test performance. Renal function tests (35%), HbA1c (23%) and lipids (17%) were the most studied laboratory tests. Most studies applied a cohort design using routinely collected health care data (49%). We found gaps in research on strategies to optimize test use to improve patient outcomes, optimal testing intervals and patient harms caused by over-testing.

CONCLUSIONS

Future research needs to address these gaps in evidence. High-level evidence is missing, i.e. randomized controlled trials comparing one monitoring strategy to another or quasi-experimental designs such as interrupted time series analysis if trials are not feasible.

Association of Acute Increases in Plasma Creatinine after Renin-Angiotensin Blockade with Subsequent Outcomes

BACKGROUND AND OBJECTIVES

Data from observational and interventional studies provide discordant results regarding the relationship between creatinine increase after renin-angiotensin system inhibition (RASi) and adverse outcomes. We compared health outcomes among patients with different categories of increase in creatinine upon initiation of RASi in a large population-based cohort.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We performed a retrospective analysis of the Stockholm CREAtinine Measurements database, which contains complete information on diagnoses, medication dispensation claims, and laboratory test results for all Stockholm citizens accessing health care. Included were 31,951 adults initiating RASi during 2007-2011 with available pre- and postinitiation creatinine monitoring. Multivariable Cox regression was used to compare mortality, cardiovascular and ESKD events among individuals with different ranges of creatinine increases within 2 months after starting treatment.

RESULTS

In a median follow-up of 3.5 years, acute increases in creatinine were associated with mortality (3202 events) in a graded manner: compared with creatinine increases <10%, a 10%-19% increase showed an adjusted hazard ratio (HR) of 1.15 (95% confidence interval [95% CI], 1.05 to 1.27); HR 1.22 (95% CI, 1.07 to 1.40) for 20%-29%; HR 1.55 (95% CI, 1.36 to 1.77) for ≥30%. Similar graded associations were present for heart failure (2275 events, P<0.001) and ESKD (52 events; P<0.001), and, less consistently, myocardial infarction (842 events, P=0.25). Results were robust across subgroups, among continuing users, when patients with decreases in creatinine were excluded from the reference group, and after accounting for death as a competing risk.

CONCLUSIONS

Among real-world monitored adults, increases in creatinine (>10%) after initiation of RASi are associated with worse health outcomes. These results do not address the issue of discontinuation of RASi when plasma creatinine increases but do suggest that patients with increases in creatinine have higher subsequent risk of cardiovascular and kidney outcomes.

Quality of Care for Patients With Chronic Kidney Disease in the Primary Care Setting: A Retrospective Cohort Study From Ontario, Canada

BACKGROUND

Patients with chronic kidney disease may not be receiving recommended primary renal care.

OBJECTIVE

To use recently established primary care quality indicators for chronic kidney disease to determine the proportion of patients receiving recommended renal care.

DESIGN

Retrospective cohort study using administrative data with linked laboratory information.

SETTING

The study was conducted in Ontario, Canada, from 2006 to 2012.

PATIENTS

Patients over 40 years with chronic kidney disease or abnormal kidney function in primary care were included.

MEASUREMENTS

In total, 11 quality indicators were assessed for chronic kidney disease identified through a Delphi panel in areas of screening, monitoring, drug prescribing, and laboratory monitoring after initiating an angiotensin converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB).

METHODS

We calculated the proportion and cumulative incidence at the end of follow-up of patients meeting each indicator and stratified results by age, sex, cohort entry, and chronic kidney disease stage.

RESULTS

Less than half of patients received follow-up tests after an initial abnormal kidney function result. Most patients with chronic kidney disease received regular monitoring of serum creatinine (91%), but urine albumin-to-creatinine monitoring was lower (70%). A total of 84% of patients age 66 and older did not receive a non-steroidal anti-inflammatory drug prescription of at least 2-week duration. Three quarters of patients age 66 and older were on an ACE inhibitor or ARB, and 96% did not receive an ACE inhibitor and ARB concurrently. Among patients 66 to 80 years of age with chronic kidney disease, 65% were on a statin. One quarter of patients age 66 and older who initiated an ACE inhibitor or ARB had their serum creatinine and potassium monitored within 7 to 30 days.

LIMITATIONS

This study was limited to people in Ontario with linked laboratory information.

CONCLUSIONS

There was generally strong performance across many of the quality of care indicators. Areas where more attention may be needed are laboratory testing to confirm initial abnormal kidney function test results and monitoring serum creatinine and potassium after initiating a new ACE inhibitor or ARB.

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

OBJECTIVES

To examine adherence to serum creatinine and potassium monitoring and discontinuation guidelines following initiation of treatment with ACE inhibitors (ACEI) or angiotensin receptor blockers (ARBs); and whether high-risk patients are monitored.

DESIGN

A general practice-based cohort study using electronic health records from the UK Clinical Practice Research Datalink and Hospital Episode Statistics.

SETTING

UK primary care, 2004-2014.

SUBJECTS

223 814 new ACEI/ARB users.

MAIN OUTCOME MEASURES

Proportion of patients with renal function monitoring before and after ACEI/ARB initiation; creatinine increase ≥30% or potassium levels >6 mmol/L at first follow-up monitoring; and treatment discontinuation after such changes. Using logistic regression models, we also examined patient characteristics associated with these biochemical changes, and with follow-up monitoring within the guideline recommendation of 2 weeks after treatment initiation.

RESULTS

10% of patients had neither baseline nor follow-up monitoring of creatinine within 12 months before and 2 months after initiation of an ACEI/ARB, 28% had monitoring only at baseline, 15% only at follow-up, and 47% both at baseline and follow-up. The median period between the most recent baseline monitoring and drug initiation was 40 days (IQR 12-125 days). 34% of patients had baseline creatinine monitoring within 1 month before initiating therapy, but <10% also had the guideline-recommended follow-up test recorded within 2 weeks. Among patients experiencing a creatinine increase ≥30% (n=567, 1.2%) or potassium level >6 mmol/L (n=191, 0.4%), 80% continued treatment. Although patients with prior myocardial infarction, hypertension or baseline potassium >5 mmol/L were at high risk of ≥30% increase in creatinine after ACEI/ARB initiation, there was no evidence that they were more frequently monitored.

CONCLUSIONS

Only one-tenth of patients initiating ACEI/ARB therapy receive the guideline-recommended creatinine monitoring. Moreover, the vast majority of the patients fulfilling postinitiation discontinuation criteria for creatinine and potassium increases continue on treatment.

Appropriate baseline laboratory testing following ACEI or ARB initiation by Medicare FFS beneficiaries

BACKGROUND

Laboratory testing to identify contraindications and adverse drug reactions is important for safety of patients initiating angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs). Rates and predictors of appropriate testing among Medicare fee-for-service beneficiaries are unknown.

PURPOSE

The study's purpose was to examine baseline laboratory testing rates, identify predictors of suboptimal testing, and assess the prevalence of abnormal creatinine and potassium among beneficiaries initiating ACE inhibitors or ARBs.

DESIGN AND SUBJECTS

Retrospective cohort of 101 376 fee-for-service beneficiaries from 10 eastern US states in 1 July to 30 November 2011.

MAIN MEASURES

Appropriate monitoring for serum creatinine or serum potassium was defined as evidence of an outpatient claim within 180 days before or 14 days after the index prescription fill date.

KEY RESULTS

Thirty-eight percent of beneficiaries were men, 78% were White race, 26% had prevalent heart failure, and 89% had prevalent hypertension. Rates of appropriate baseline laboratory testing were 82.7% for potassium, 83.2% for creatinine, and 82.6% for both potassium and creatinine 180 days prior to initiation. In logistic regression, men (odds ratio [OR] = 1.15, 95% confidence interval [CI]: 1.11, 1.19), African-Americans (OR = 1.26, 95%CI: 1.20, 1.32), and beneficiaries with Alzheimer's disease and related disorders (OR = 1.22, 95%CI: 1.15, 1.28) or stroke (OR = 1.34, 95%CI: 1.26, 1.43) were more likely to experience suboptimal testing. At baseline, hyperkalemia was relatively uncommon (5.8%), and elevated creatinine values were rare (1.4%).

CONCLUSIONS

Appropriate monitoring could be improved for African-American beneficiaries and beneficiaries with a history of stroke or Alzheimer's disease and related disorders initiating ACE inhibitors or ARBs. Copyright © 2016 John Wiley & Sons, Ltd.

Adherence to renal function monitoring guidelines in patients starting antihypertensive therapy with diuretics and RAAS inhibitors: a retrospective cohort study

BACKGROUND

Acute kidney injury (AKI) might complicate antihypertensive therapy. In The Netherlands, general practitioner clinical practice guidelines provide clear recommendations on monitoring of renal function to minimize this risk. Our objective was to investigate how day-to-day clinical practice corresponds to the guidelines.

METHODS

We conducted a retrospective cohort study in a dynamic population, using data on >9,000 adults that was retrieved from the Integrated Primary Care Information database. We investigated whether serum creatinine (SCR) was measured within 30 and 365 days after the start of (combined) use of a diuretic, an angiotensin-converting enzyme inhibitor, and/or angiotensin receptor blocker. We also investigated the association between calendar year, sex, type of therapy, risk factors for AKI and practice and SCR measurement.

RESULTS

Of 6,593 subjects who met the study criteria for single drug therapy, SCR was measured in 1,233 subjects within 30 days and in 3,896 subjects within 365 days. For combined drug therapy recipients (n = 2,497), these were 545 and 1,687, respectively. Associated cumulative probabilities were 19 % and 66 % with single drug therapy, and 22 % and 74 % with combined drug therapy. Significant differences were observed between practices. SCR measurement was associated with other characteristics, except for sex. Within 365 days, SCR increased >30 % of baseline in 103 subjects (1.6 %) after the start of single drug therapy, and in 85 (3.4 %) subjects who initiated combined drug therapy. In the majority (>70 %) of these subjects, this did not result in subsequent monitoring or adjustment of antihypertensive treatment.

CONCLUSIONS

Results from this study suggest that, on average, renal function is not monitored as strictly as recommended by relevant clinical practice guidelines.

A practical guide to monitoring for adverse drug reactions during antihypertensive drug therapy

Monitoring of patients taking antihypertensive treatment can identify potential adverse drug reactions (ADRs). However, published guidelines give divergent or incomplete recommendations on monitoring for ADRs. Using a predetermined strategy, we undertook a systematic review to identify hypertension guidelines published from January 2001 to October 2011 with recommendations for monitoring for ADRs. We screened 88 abstracts and 187 web-based guidelines, and identified 19 published guidelines on monitoring the biochemical effects of antihypertensive drug therapy. We then produced a set of practical clinical guidelines, synthesized from those recommendations. Our recommendations are designed to provide efficient monitoring. They reduce the number of tests to a minimum consistent with safe practice and align monitoring schedules, so that creatinine, potassium and sodium concentrations are measured at the same times in all cases. The instructions for biochemical monitoring in current guidelines differ greatly, both in the extent of advice and in the detail provided. The current lack of consistent and workable instructions poses serious difficulties for practitioners. The recommendations distilled from this systematic review should help practitioners when they monitor therapy with antihypertensive drugs.

Pharmacoepidemiology

Current concerns over the safety of medicines once they have been marketed mean that pharmacoepidemiology is of increasing importance. There are three main areas in which further research is needed. 1 To improve the methods used to make causal inference of effects of medicines and to raise the quality of the reporting and critical appraisal tools, so that the strengths and weaknesses of the new methods can be judged. 2 To apply the methods in areas where randomized trials cannot easily be done, such as in pregnancy. 3 To use electronic health records as fully as possible, using linkage between different databases, ensuring the data are of as high quality as possible. Public health and public perceptions mean that much of pharmacoepidemiology must be done using non-industry funding sources.

Biochemical monitoring of patients treated with antihypertensive therapy for adverse drug reactions: a systematic review

Biochemical monitoring of patients treated with antihypertensive therapy is recommended in order to identify potential adverse reactions to treatment. We aimed to review the literature investigating the nature of biochemical monitoring in adults treated in primary care with antihypertensive drugs. Specifically, we wished to establish (i) the proportion of patients with biochemical baseline testing prior to the initiation of antihypertensive therapy; (ii) the proportion of patients with biochemical monitoring after initiation of antihypertensive therapy; (iii) the patient characteristics associated with biochemical monitoring; (iv) the frequency of biochemical monitoring after the initiation of antihypertensive therapy; and (v) the relationship, if any, between biochemical monitoring and adverse patient outcomes. We searched MEDLINE, EMBASE and Google Scholar from 1948 to 31 December 2010 using a combination of text words and search terms. Retrospective and prospective cohort studies, cross-sectional studies, randomized controlled trials or quasi-randomized controlled trials, and audits of current clinical practice were included. Clinical trials, case reports and case series were excluded. Studies were included if they provided data on the proportion of patients treated with antihypertensive therapy in primary care who had any biochemical monitoring before or after the initiation of therapy. In total, 15 studies were included in our review, which used a wide variety of definitions of monitoring prior to and after the initiation of antihypertensive therapy. From 17% to 81% of patients treated with antihypertensive drugs had a baseline biochemical test and from 20% to 79% had any follow-up monitoring. In only 7 of the 12 studies that examined follow-up monitoring did more than half of the patients have any monitoring. Overall, this systematic review provides evidence that monitoring as recommended by published guidelines is not commonly undertaken. Only two studies were identified that examined patients with both baseline testing and follow-up monitoring. Omission of one or the other limits the ability to analyse the effect of treatment on electrolyte concentrations or renal function. There is limited research on the patient factors associated with monitoring and further work is required to determine the impact of monitoring on adverse patient outcomes. Important barriers to effective monitoring exist and this review emphasizes that these have not yet been overcome.

Adherence to biochemical monitoring recommendations in patients starting with renin angiotensin system inhibitors: a retrospective cohort study in the Netherlands

BACKGROUND

Renin angiotensin system inhibitors (RASIs) are frequently involved in serious adverse events. These events principally occur in high-risk patients and often arise within the first days after treatment initiation; therefore, guidelines recommend biochemical monitoring within 3 weeks after the start of therapy with RASIs.

OBJECTIVE

The purpose of this study was to examine the level of biochemical monitoring directly after treatment initiation with RASIs in patients with different risk profiles and to study the attitudes of the physicians involved towards biochemical monitoring.

METHODS

We carried out a retrospective analysis of 202 patients who started RASI therapy in 2006 in Groesbeek, the Netherlands. We determined the rate of serum creatinine and potassium monitoring within 3 weeks after the start of therapy. In addition, we studied the intentions and attitudes towards biochemical monitoring during RASI therapy among 68 general practitioners and medical specialists by way of a brief questionnaire.

RESULTS

Serum creatinine and potassium monitoring after treatment initiation was performed in 34% and 28% of patients, respectively. Of all the patients, 29% had two or more additional risk factors for renal function deterioration. In these high-risk patients, creatinine was significantly less often monitored compared with low-risk patients (22% vs 39%). In contrast to these findings, the prescribing physicians claimed to check serum creatinine within 2 weeks after treatment initiation in 85% of their patients. Most of the prescribing physicians (88%) rated this monitoring as (very) important.

CONCLUSIONS

We demonstrated that, despite positive intentions of physicians, the biochemical monitoring recommendation in patients treated with RASIs is poorly met. In addition, serum creatinine monitoring was significantly less often performed in high-risk patients compared with low-risk patients.

Laboratory monitoring and adverse patient outcomes with antihypertensive therapy in primary care

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.