INTRODUCTION

Atrial fibrillation (AF) is considered to be one of the major causes of stroke and heart failure. ¹ In a systematic review, Chugh et al. reported a progressive increase in global prevalence of AF with higher rates observed in the older age groups. ² Management recommendations focus on reducing thromboembolic risk and on rate and rhythm control. ¹ , ³ , ⁴ , ⁵ Although recent data shows good progress in the management of patients with AF, there is still substantial evidence of suboptimal therapy. ⁶, ⁷, ^{8 9}

A number of drug utilisation review tools have been developed for the purpose of identifying potentially inappropriate drug therapy, predominantly targeting the older population from a generic perspective rather than for specific disease states. ¹⁰ , ¹¹ Only some aspects of AF management have been incorporated in these tools, the most commonly cited being the Beers’ Criteria ¹² , the Screening Tool of Older Persons’ Prescriptions (STOPP) and the Screening Tool to Alert Doctors to Right Treatment (START). ¹³ Medication assessment tools (MATs) are disease-specific, evidence-based instruments designed to assess appropriateness of drug therapy and have been developed and applied in various diseases including heart failure, diabetes mellitus, coronary heart disease, cancer pain, asthma, pneumonia and rheumatoid arthritis. ¹⁴ , ¹⁵ , ¹⁶ , ¹⁷ , ¹⁸ , ¹⁹ , ²⁰ , ²¹ A MAT that is specific for AF, taking into consideration different management strategies, concurrent multiple morbidities and monitoring for safe use of therapeutic agents, provides an assessment of appropriateness of drug therapy for this disease state.

The aim of the study was to design, psychometrically evaluate and apply an innovative MAT for the long-term management of AF, with particular relevance to older persons, so as to assess adherence to guideline recommendations.

METHODS

RESULTS

In the first round of the Delphi validation process, consensus was achieved for eight of the fifteen criteria in MAT-AF. Adjustments were made to five criteria, two criteria were removed and three new criteria were created. In the second validation round, consensus was obtained for all sixteen criteria. A third round was necessary to review three criteria which were adjusted to reflect guideline updates regarding digoxin use following which consensus was achieved for two criteria and one criterion was removed. MAT-AF after validation was composed of fifteen review criteria sectioned into antithrombotic, rate control and rhythm control therapy. Details on criteria validation may be viewed in Table 1 of the supplementary material .

Reliability testing resulted in kappa values of 0.84 (p<0.001) and 0.91 (p<0.001) for inter- and intra-observer agreements. Mean application time was 3.90 (SD=1.18) minutes for observer 1 and 2.38 (SD=0.95) minutes for observer 2. Following the four-week period, mean application time for observer 1 was 2.12 (SD=0.92) minutes and 1.56 (SD=0.41) minutes for observer 2, both significantly lower than the time for the first application (p<0.001). Correlations were significant for both inter-observer (r=0.5, p=0.005) and intra-observer tests (r=0.7, p<0.001 and r=0.5, p=0.008).

Patient characteristics and MAT-adherence results of the 150 patients assessed during MAT-AF application are shown in Table 1 and Table 2 , respectively. Adherence to the applicable criteria was 59.8% and justified non-adherence was 11.1%. Non-adherence was evident for prescription of anticoagulation in patients with a CHA ₂DS₂VASc score ≥1 (29.5%). Monitoring of laboratory parameters relating to digoxin therapy was deficient in 49.1% of patients, predominantly due to absence of magnesium levels, and in 26.1% of patients at risk of high serum digoxin concentrations. Ophthalmic and pulmonary monitoring and patient counselling regarding amiodarone therapy could not be assessed as relevant records were not readily available. Cardiology referral was not performed in most of the patients for whom it was recommendable.

DISCUSSION

Reliability of MAT-AF was confirmed and was similar to other MATs. ¹⁶ , ¹⁹ , ²⁰ There was a significant correlation for the two observers in the time spent on MAT-AF application for the same patient case. Following the four-week interval, the application time for both observers was significantly lower compared to the first application, possibly indicating that repeated use of the MAT facilitates application. The short application time supports application of MAT-AF in a clinical setting.

Specific aspects that are applicable to a few patients were also included in the MAT resulting in a low applicability for these criteria when considering the entire patient cohort. The incorporation of such criteria is clinically relevant as otherwise important aspects may be overlooked.

Application of MAT-AF indicated the need for increased prescribing of anticoagulation in the study population. Underutilisation of anticoagulation, particularly in the older population, has been reported in several studies. ⁷ - ⁹ Appropriate anticoagulation is particularly important among older persons since this patient group is at greater risk of stroke attributable to AF. ²² Recurrent falls or a high risk for falls was a common reason for withholding anticoagulation therapy in the study population as has been reported in other studies. ⁸ , ²³ , ²⁴ Although AF guidelines caution the use of anticoagulation therapy in patients at risk for falls, recommendations specify that these agents should only be withheld in patients with severe uncontrolled falls such as epilepsy or advanced multisystem atrophy with backward falls. ¹

Monitoring of laboratory and other parameters is recommended to reduce complications of AF therapy. ¹ Chronic kidney disease, other comorbidities and multiple medication increase the risk of adverse drug reactions in this patient group. MAT-AF application highlighted deficiencies in the monitoring required with digoxin therapy, predominantly regarding serum magnesium and digoxin levels in patients at risk of toxicity. Shortcomings were also evident in assessing whether the required monitoring with amiodarone was conducted.

Guidelines for the management of AF emphasize that patients on antiarrhythmic agents should be periodically evaluated to confirm appropriateness of treatment. ¹ Drug therapy which was favourable when initially prescribed may not remain effective in maintaining sinus rhythm or may become inappropriate once the patient develops additional comorbidities. During MAT-AF development, cardiology referral was considered recommendable in these patients. In this study there was a tendency for treatment decisions to be taken without cardiology referral, predominantly resulting in patients being retained on antiarrhythmic agents despite sinus rhythm not being maintained.

The application of MAT-AF has led to identification of areas for improvement in terms of prescribing of anti-thrombotics, monitoring parameters to ensure drug safety and identification of patients warranting referral. MAT-AF additionally provides a means for individual patient assessment by the clinical team to identify patient-specific therapy needs. In a follow-up study, MAT-AF is being implemented by clinical pharmacists at the rehabilitation hospital to assess whether application of the tool in daily practice enhances optimisation of treatment.

CONCLUSIONS

MAT-AF application highlighted key aspects which need to be addressed. The application of such tools in clinical practice can support the challenging task of optimising drug therapy in older persons.