Frequency of Serum Creatinine Monitoring During Allopurinol Therapy in Ambulatory Patients

A novel algorithm for detection of adverse drug reaction signals using a hospital electronic medical record database

PURPOSE

Quantitative analytic methods are being increasingly used in postmarketing surveillance. However, currently existing methods are limited to spontaneous reporting data and are inapplicable to hospital electronic medical record (EMR) data. The principal objectives of this study were to propose a novel algorithm for detecting the signals of adverse drug reactions using EMR data focused on laboratory abnormalities after treatment with medication, and to evaluate the potential use of this method as a signal detection tool.

METHODS

We developed an algorithm referred to as the Comparison on Extreme Laboratory Test results, which takes an extreme representative value pair according to the types of laboratory abnormalities on the basis of each patient's medication point. We used 10 years' EMR data from a tertiary teaching hospital, containing 32,033,710 prescriptions and 115,241,147 laboratory tests for 530,829 individual patients. Ten drugs were selected randomly for analysis, and 51 laboratory values were matched. The sensitivity, specificity, positive predictive value, and negative predictive value of the algorithm were calculated.

RESULTS

The mean number of detected laboratory abnormality signals for each drug was 27 (±7.5). The sensitivity, specificity, positive predictive value, and negative predictive value of the algorithm were 64-100%, 22-76%, 22-75%, and 54-100%, respectively.

CONCLUSION

The results of this study demonstrated that the Comparison on Extreme Laboratory Test results algorithm described herein was extremely effective in detecting the signals characteristic of adverse drug reactions. This algorithm can be regarded as a useful signal detection tool, which can be routinely applied to EMR data.

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

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.

Doctors' perceptions of laboratory monitoring in office practice

BACKGROUND

Laboratory monitoring has been increasingly recognized as an important area for improving patient safety in ambulatory care. Little is known about doctors' attitudes towards laboratory monitoring and potential ways to improve it.

METHODS

Six focus groups and one individual interview with 20 primary care doctors and nine specialists from three Massachusetts communities.

RESULTS

Participants viewed laboratory monitoring as a critical, time-consuming task integral to their practice of medicine. Most believed they commit few laboratory monitoring errors and were surprised at the error rates reported in the literature. They listed various barriers to monitoring, including not knowing which doctor was responsible for ensuring the completion of laboratory monitoring, uncertainty regarding the necessity of monitoring, lack of alerts/reminders and patient non-adherence with recommended monitoring. The primary facilitator of monitoring was ordering laboratory tests while the patient is in the office. Primary care doctors felt more strongly than specialists that computerized alerts could improve laboratory monitoring. Participants wanted to individualize alerts for their practices and warned that alerts must not interrupt work flow or require too many clicks.

CONCLUSIONS

Doctors in community practice recognized the potential of computerized alerts to enhance their monitoring protocols for some medications. They viewed patient non-adherence as a barrier to optimal monitoring. Interventions to improve laboratory monitoring should address doctor workflow issues, in addition to patients' awareness of the importance of fulfilling recommended therapeutic monitoring to prevent adverse drug events.

Optimizing therapy with allopurinol: factors limiting hypouricemic efficacy

The aim of this review is to examine clinical aspects of the use of the hypouricemic drug allopurinol. Allopurinol is a moderately active hypouricemic drug. Its activity is largely the result of the inhibition of xanthine oxidoreductase by oxypurinol, the active metabolite of allopurinol. The activity of allopurinol may be limited by oxypurinol, reducing the renal clearance of urate. Optimal use of allopurinol involves individualization of dose to attain a sufficient decrease in plasma urate concentrations. This may require a dose greater than recommended based on creatinine clearance. The initial use of an anti-inflammatory drug or low-dose colchicine decreases but does not eliminate the development of acute attacks of gout during the initiation of therapy with allopurinol. Monitoring of oxypurinol concentrations has shed some light on the efficacy of allopurinol but more data are required particularly in patients with renal impairment. Probenecid increases the hypouricemic effect of allopurinol but the favorable interaction may be significant only in patients with glomerular filtration rates greater than about 50 mL/min.

Gold salts, D-penicillamine and allopurinol

Gold salts have been used in the treatment of patients with rheumatoid arthritis since 1927 [1]. After a controlled study, the Empire Rheumatism Council [2], confirmed the effectiveness of gold salts for the treatment of rheumatoid arthritis. Even today, chrysotherapy has remained one of the major therapeutic modalities in the second line treatment of progressive rheumatoid arthritis. Gold salts are also used in the treatment of pemphigus vulgaris [3] and bronchial asthma [4]. Before the introduction of an orally administered gold compound, auranofin (triethylphosphine gold tetra-acetyl glycopyranoside), to clinical use [5-7], parenterally administered gold salts, such as sodium aurothiomalate and gold thioglucose comprised chrysotherapy. The frequency and severity of the side effects for patients treated with parenteral gold versus those given oral gold preparations are significantly different [8-10]. With introduction of newer parental DMARDs, toxicity has been reduced using combination therapy [10a, 10b].

Therapeutic advances in gout

PURPOSE OF REVIEW

The purpose of this review is to highlight the recent developments in the management of gout.

RECENT FINDINGS

Guidelines for the diagnosis and management of gout from EULAR, quality of care indicators, and outcome measures for clinical trials have been published. The standards of gout diagnosis and management are very low. Allopurinol remains the mainstay for serum uric acid lowering therapy. In an important percentage of patients receiving allopurinol, serum uric acid levels are insufficient to promote crystal dissolution. Febuxostat, a new serum uric acid lowering drug, has shown good results. Information on uricase continues to appear. For treatment of gouty inflammation, etoricoxib (a new cyclooxygenase 2 inhibitor) has been shown to be as effective as indomethacin. Finally, the association of gout with the metabolic syndrome and its comorbidities, and the newly described association of gout with myocardial infarction, bring lifestyle and dietary modifications to the front in the management of gout.

SUMMARY

Proper gout management requires changes to the physician's attitude towards the disease; essentially: (1) an unequivocal diagnosis based in urate crystal identification, (2) a clearly settled aim of the treatment: crystal elimination from the joints and elsewhere, and (3) proper use of the available therapeutic alternatives. Promoting a proper lifestyle appears to be especially important.

Linking laboratory and medication data: new opportunities for pharmacoepidemiological research

Transfer of automated laboratory data collected during routine clinical care from the laboratory information system into a database format that enables linkage to other administrative (e.g., patient characteristics) or clinical (e.g., medication, diagnoses, procedures) data provides a valuable tool for clinical epidemiological research. It allows the investigation of biochemical characteristics of diseases, therapeutic effects and diagnostic and/or prognostic markers for disease with easy access and at relatively low cost. To this end, the Utrecht Patient Oriented Database (UPOD), an infrastructure of relational databases comprising data on patient characteristics, laboratory test results, medication orders, hospital discharge diagnoses and medical procedures for all patients treated at the University Medical Centre Utrecht since January 2004, was established. Current research within UPOD is focused on the innovative linkage of laboratory and medication data, which, for example, makes it possible to assess the quality of pharmacotherapy in clinical practice, to investigate interference between laboratory tests and drugs, to study the risk of adverse drug reactions, and to develop diagnostic and prognostic markers or algorithms for adverse drug reactions. Although recently established, we believe that UPOD broadens the opportunities for clinical pharmacoepidemiological research and can contribute to patient care from a laboratory perspective.

Febuxostat: a selective xanthine oxidase inhibitor for the treatment of hyperuricemia and gout

OBJECTIVE

To review the pharmacology, pharmacokinetics, clinical trial data, safety profile, precautions, and place in therapy of febuxostat, a novel nonpurine xanthine oxidase inhibitor in development for the treatment of hyperuricemia and gout.

DATA SOURCES

Available studies and abstracts were identified through MEDLINE (1990-November 2006), Science Citation Index, International Pharmaceutical Abstracts, Cochrane Databases, and the American College of Rheumatology and European League Against Rheumatism Web sites. Key search terms were febuxostat, TMX-67, TEI-6720, hyperuricemia, and gout.

STUDY SELECTION AND DATA EXTRACTION

All available studies describing the pharmacology of febuxostat were included. Human studies formed the basis for discussion of clinical parameters, including pharmacokinetics, pharmacodynamics, efficacy, and safety of febuxostat.

DATA SYNTHESIS

Febuxostat significantly reduces uric acid levels within 2 weeks after initiation of therapy and up to 48% by the end of 104 weeks of therapy. Approximately 60% of patients achieved the primary goal of serum uric acid less than 6 mg/dL during the last 3 months following once-daily administration of febuxostat 80 mg or 120 mg for at least 52 weeks. The most common adverse reactions to febuxostat were abnormal results from liver function tests, diarrhea, headache, arthralgias, and musculoskeletal symptoms. Due to its potency, patients are at an increased risk of experiencing gout flares for at least the first year of therapy. Up to 70% of patients in clinical trials experienced gout flares despite concomitant prophylactic treatment with colchicine or naproxen. Additional clinical trial evidence supports the efficacy and safety of febuxostat in the treatment of hyperuricemia and gout.

CONCLUSIONS

Febuxostat is a promising alternative to allopurinol for the treatment of gout and hyperuricemia. The optimal length of prophylactic therapy, clinical significance of abnormal liver function tests results during therapy, and safety in patients with moderate or severe renal insufficiency warrant further investigation.