The effect of an educational intervention on meperidine use in Nova Scotia, Canada: a time series analysis

Abstract

Purpose: To evaluate the impact of a prescriber focused individual educational and audit-feedback intervention undertaken by the Nova Scotia Prescription Monitoring Program (NSPMP) in March/April 2007 to reduce meperidine use.

Method: The NSPMP records all prescriptions for controlled substances dispensed in community pharmacies in Nova Scotia, Canada. Oral meperidine use from 1 July 2005 to 31 December 2009 was examined using NSPMP data. Monthly totals for the following were obtained: number of individual patients who filled at least one meperidine prescription, number of prescriptions, and number of tablets dispensed. Data were analyzed graphically to observe overall trends. The intervention effect was estimated on the logarithmic scale with autocorrelations over time modeled by an integrated autoregressive moving average model for each outcome measure.

Results: An overall trend toward decreasing use from July 2005 to December 2009 was apparent for all three outcome measures. The intervention was associated with a statistically significant reduction in meperidine use, after adjusting for the overall long-term trend. Compared with the pre-intervention period, the monthly number of patients declined by 12% (p < 0.001; 95% confidence interval [CI] = 5%-18%), prescriptions by 10% (p < 0.001; 95%CI = 3%-17%), and tablets by 13.5% (p < 0.001, 95%CI = 6%-29%) in the post-intervention period.

Conclusion: Given the risks associated with meperidine, determining that this intervention successfully reduced meperidine use is encouraging. This study highlights the potential for using population data such as the NSPMP to evaluate the effectiveness of population-level interventions to improve medication use, including professional, organizational, financial, and regulatory initiatives.

Figure 1

Monthly number of patients before intervention (July 2005–March 2007) and after intervention (April 2007–December 2009). The dotted line is the LOWESS smoothing line. The solid vertical line is the time of the educational intervention

Figure 2

Monthly number of prescriptions before intervention (July 2005–March 2007) and after intervention (April 2007–December 2009). The dotted line is the LOWESS smoothing line. The solid vertical line is the time of the educational intervention

Figure 3

Monthly number of tablets before intervention (July 2005–March 2007) and after intervention (April 2007–December 2009). The dotted line is the LOWESS smoothing line. The solid vertical line is the time of the educational intervention