Factor analysis improves the selection of prescribing indicators

Quality of prescribing for hypertension and bronchial asthma at a tertiary health care facility, India using Prescription Quality Index tool

OBJECTIVE

Several tools have been introduced to evaluate the quality of prescribing. The aim of this study was to determine the quality of prescribing in hypertension and bronchial asthma in tertiary health care (THC) setting using the new Prescription Quality Index (PQI) tool and to assess the reliability of this tool.

METHODS

A prospective cross-sectional study was carried out for 2 months in order to assess the quality of prescribing of antihypertensive and antiasthmatic drugs using recently described PQI at THC facility. Patients with hypertension and bronchial asthma, attending out-patient departments of internal medicine and pulmonary medicine respectively for at least 3 months were included. Complete medical history and prescriptions received were noted. Total and criteria wise PQI scores were derived for each prescription. Prescriptions were categorized as poor, medium and high quality based on total PQI scores.

RESULTS

A total of 222 patients were included. Mean age was 56 ± 15.1 years (range 4-87 years) with 67 (30.2%) patients above 65 years of age. Mean total PQI score was 32.1 ± 5.1. Of 222 prescriptions, 103 (46.4%) prescriptions were of high quality with PQI score ≥34. Quality of prescribing did not differ between hypertension and bronchial asthma (P > 0.05). The value of Cronbach's α for the entire 22 criteria of PQI was 0.71.

CONCLUSION

As evaluated by PQI tool, the quality of prescribing for hypertension and bronchial asthma is good in about 47% of prescriptions at THC facility. PQI is valid for measuring prescribing quality in these chronic diseases in Indian setting.

Development of a minimal set of prescribing quality indicators for diabetes management on a general practice level

OBJECTIVE

To identify the relevant prescribing quality domains of type 2 diabetes mellitus care as a basis for the selection of a minimal set of prescribing quality indicators from a set of previously validated indicators.

METHODS

We used the principal factor analysis to identify the underlying dimensions or domains of prescribing quality for 76 general practitioners participating to the Groningen Initiative to Analyse Type 2 Diabetes Treatment project in the Netherlands. From a set of 10 prescribing quality indicators covering various aspects of cardiovascular and metabolic management, we selected a subset of indicators with the highest loading within each identified domain. Next, we evaluated the effect of using this subset on the quintile ranking of practices on their prescribing quality scores.

RESULTS

We identified five prescribing quality domains in our data set: two assessing initiation of pharmacotherapy for different risk factors in diabetic patients, two on stepwise intensification of treatment, and one on treatment of patients with cardiovascular disease. A composite score comprising the indicators selected from each of the domains showed good agreement with the composite score comprising all indicators with 82% of general practitioners either not changing their position or shifting their ranking by only one quintile.

CONCLUSIONS

We showed that a minimal set of prescribing quality indicators for type 2 diabetes mellitus care should not just focus on the management of different clinical risk factors but also reflect different steps of treatment intensification. The results of our study are relevant for stakeholders when selecting quality indicators to assess the quality of prescribing in diabetic patients.

Development and validation of a new Prescription Quality Index

AIMS

The aims were to develop and validate a new Prescription Quality Index (PQI) for the measurement of prescription quality in chronic diseases.

METHODS

The PQI were developed and validated based on three separate surveys and one pilot study. Criteria were developed based on literature search, discussions and brainstorming sessions. Validity of the criteria was examined using modified Delphi method. Pre-testing was performed on 30 patients suffering from chronic diseases. The modified version was then subjected to reviews by pharmacists and clinicians in two separate surveys. The rater-based PQI with 22 criteria was then piloted in 120 patients with chronic illnesses. Results were analysed using SPSS version 12.0.1

RESULTS

Exploratory principal components analysis revealed multiple factors contributing to prescription quality. Cronbach's α for the entire 22 criteria was 0.60. The average intra-rater and inter-rater reliability showed good to moderate stability (intraclass correlation coefficient 0.76 and 0.52, respectively). The PQI was significantly and negatively correlated with age (correlation coefficient -0.34, P<0.001), number of drugs in prescriptions (correlation coefficient -0.51, P<0.001) and number of chronic diseases/conditions (correlation coefficient -0.35, P<0.001).

CONCLUSIONS

The PQI is a promising new instrument for measuring prescription quality. It has been shown that the PQI is a valid, reliable and responsive tool to measure quality of prescription in chronic diseases.