Quality assurance of prescribing in the elderly population

Abstract

Several characteristics of ageing make the selection of appropriate drug therapy a complex and challenging task. Inappropriate prescribing is highly prevalent in older persons and can be associated with increased morbidity, mortality and demands on healthcare resources. Clinical practice guidelines and other information sources are becoming increasingly available to aid in the process of improving the quality of drug therapy. The diverse information needs to be incorporated into structured drug therapy assessment systems to facilitate application, particularly in older persons who often have multiple morbidities. Drug therapy assessment systems provide a means of assessing appropriateness of drug therapy and when incorporated within practice settings may facilitate a systematic approach to identifying pharmaceutical care issues for pharmacist intervention. Documentation of the pharmacist interventions and of the outcomes of the decisions taken by the interdisciplinary health care team is important so that the care provided is recorded. The aim of this research was to develop innovative tools to assess appropriateness of drug therapy and to evaluate whether implementation of these tools in clinical practice contributed to optimisation of therapy in older persons. The main outcome of this research was the development and clinical implementation of medication assessment tools (MATs) specific to the secondary prevention of stroke (MAT-CVA) and the long term management of atrial fibrillation (MAT-AF). International clinical practice guidelines for stroke and atrial fibrillation were reviewed and a guideline comparison compiled for each disease state incorporating the grading of evidence. Review criteria defining appropriate drug therapy were selected from the guidelines and the two MATs constructed. An application guide for consistent interpretation and application of the MATs was also compiled. Following testing for content validity, reliability and feasibility, the MATs were applied as audit tools by the researcher in a retrospective study of 150 patients with stroke and 150 patients with atrial fibrillation admitted to Rehabilitation Hospital Karin Grech. Adherence to MAT review criteria and pharmacist intervention were assessed. This was followed by implementation of the MATs for use as clinical tools by the pharmacists in the hospital as part of their daily practice. A training programme was conducted to introduce the MATs to the clinical pharmacists following which the MAT review criteria were applied for identification of pharmaceutical care issues to be followed by the respective intervention and documentation. Adherence to the MATs and intervention documentation was subsequently audited post-MAT implementation for a further 300 patients (150 for each disease state) to assess whether application of the tool in clinical practice improved adherence to review criteria and pharmacist intervention. The developed MAT-CVA consists of 17 criteria sectioned into antithrombotic, lipid lowering, antihypertensive and glycaemic therapy. MAT-AF consists of 15 criteria sectioned into antithrombotic, rate control and rhythm control therapy. Content validity was demonstrated for all MAT criteria. Reliability of MAT-CVA was confirmed with average kappa values of 0.80 and 0.81 for inter- and intra-observer agreements. Mean application time of MAT-CVA for two observers was 5.6 and 6.6 minutes. Reliability of MAT-AF was confirmed with average kappa values of 0.84 and 0.91 for inter- and intra-observer agreements. Mean application time of MAT-AF for the two observers was 3.9 and 2.4 minutes. A significant increase in adherence to MAT review criteria from 77.3% to 89.6% (z-score 8.64, p<0.001) was evident after implementation of MAT-CVA. Implementation resulted in a significant improvement specifically in prescription of anticoagulation in concurrent atrial fibrillation, dipyridamole at the recommended dose and thiazide diuretics +/- angiotensin converting enzyme inhibitors for hypertension. Monitoring of liver function with statins, renal function and serum potassium with angiotensin converting enzyme inhibitors, and HbA1c also improved significantly after MAT-CVA implementation. Implementation of MAT-CVA resulted in an improvement in achievement of blood pressure and HbA1c targets. Adherence to MAT review criteria increased significantly from 70.9% to 89.6% (z-score 7.09, p<0.001) after implementation of MAT-AF. Implementation resulted in a significant improvement in prescription of anticoagulation in patients with a CHA2DSNASc score ~1, rate control therapy, monitoring of laboratory and other parameters for digoxin and amiodarone, and cardiology referral in patients on antiarrhythmic agents not maintained in sinus rhythm. Pharmacist interventions improved significantly after implementation of MAT-CVA (z-score 21.66, p<0.001) and of MAT-AF (z-score 20.25, p<0.001). A significant increase in documented pharmacist interventions was evident for each pharmacist for both MATs. The review criteria incorporated in the MATs define appropriate medication selection and corresponding doses, recommend parameter targets as well as monitoring requirements to identify as well as prevent adverse drug reactions. As the MATs are intended for use in older persons, guideline recommendations relating to this patient group were given consideration to account for variations in health, functional and cognitive status. This was particularly relevant regarding the indication for and intensity of statins, targets for blood pressure, HbA1c and blood glucose, impairment of renal function in the case of oral anticoagulants, and comorbidities in the case of antihypertensive and rate control therapy. MAT-CVA and MAT-AF addressed both over- and under-prescribing in order to contribute to achieving an optimal balance between risk and benefit of drug therapy in the older patient. Justifications for non-adherence were particularly relevant as would be expected in the study population of older patients. The frequency of justified non-adherence was factored in the adherence calculation contrary to previous MAT publications which only considered ‘yes' responses as adherence. Justified non-adherence was particularly high in MAT-CVA namely 22.3% pre-implementation and 27.2% post-implementation. Implementation of MAT-CVA and MAT-AF for use by clinical pharmacists within an interdisciplinary health care team significantly improved the quality of drug therapy in older persons admitted to a rehabilitation hospital. The benefit was evident in various aspects particularly in parameter monitoring necessary to ensure safe use of drug therapy. A highly significant improvement was also demonstrated in the documentation of clinical pharmacist interventions for a" pharmacists following MAT implementation. An upgrade in documentation is especially relevant for the rehabilitation hospital as sharing of pharmacist interventions with other members of the health care team and accreditation of services becomes imminent. MAT implementation had a significant impact on the quality assurance of drug therapy in older persons and resulted in a highly significant improvement in the contribution of the clinical pharmacist. The application of such tools in clinical practice was shown to support the challenging task of optimising drug therapy in older persons.