Factors Influencing Oral Coxibs Utilization and Expenditure at a Thai Teaching Hospital, Fiscal Year 2007 to 2009

This study aimed to examine factors that influenced the rising Coxibs expenditure.

Retrospective utilization data were retrieved from hospital's database. Changes in Coxibs expenditure in 2007 and 2009, calculated by using the Laspeyres index, were attributed to two factors: cost per patient (P) and number of patients (Q) per year. By measuring quantity as defined daily dose, changes in P comprised two subfactors: cost per day (p) and days of therapy per patient (q); p was weighted average cost of Coxibs per day, and q was weighted average days of therapy of new and current patients. Furthermore, the pattern of concomitant drugs, proton pump inhibitors, was analyzed.

Expenditure on Coxibs rose from 57.7 to 69.4 million baht from 2007 to 2009. With Laspeyres index, total index of 1.20 was a result of three main factors. The highest impact was from change in cost per day (p index at 1.17), which was a result of a slight increase in drug cost, mainly weighted by product mix, which tended to switch drug from low to high cost. Another positive impact was the number of Coxibs patients (Q index at 1.04). Finally, the negative impact was from days of therapy per patient (q index = 0.98). Although days of therapy per patient for both new and current patients were decreased, patient mix of more current patients slowed the decrease down. In addition, the percentage of proton pump inhibitors coprescription also rose from 30.8% in 2007 to 32.3% in 2009.

Switching drug from low to high cost is a major factor that impacted the rising of expenditure on Coxibs.