Cost of the alternative

In order to calculate societal costs for the alternative scenario, we estimated the direct costs of the alternative, along with the average cost of OTC medications, as well as indirect costs for travel to and wait time for GP visits or the emergency room and productivity loss from inadequate care for minor ailments. First, using expert opinion and a survey of the average cost of OTCs for the five most common minor ailments covered in the PPMA program, we estimated OTC costs at $12 per medication. Cost per OTC medication along with the total number of patients who would have used OTCs in the absence of the PPMA program, projected the total cost of OTCs at $55,413 per year. Moreover, we were able to estimate the productivity loss as a result of the potential lower effectiveness of OTCs as compared to prescription drugs. For this analysis we considered five pharmacist-consulted minor ailments (allergic rhinitis, GERD, headache, cold sores and musculoskeletal pain), which accounted for 63% of pharmacist consultations in Saskatchewan and identified as being minor ailments quite likely to cause time off work and may require prescription medication for resolution. Therefore, we only considered there to be productivity losses for the 57% of individuals who would have self-treated or treated with OTCs as part of the alternative, as everyone in the PPMA program received a prescription. First, we extracted the number of days absent per year for each minor ailment from the literature [28–30]. Second, we estimated total productivity loss per day absent based on the average wage in Canada [25]. Third, we obtained data from clinical trials and a meta-analysis to estimate the relative efficacy of each of the most common OTC (OTC drug versus placebo) and prescription medications (prescription versus placebo) for the five minor ailments [31–37]. Then we estimated incremental efficacy by subtracting efficacy of prescription compared to placebo from the efficacy of OTC compared to placebo. We then calculated the incremental productivity loss cost as a result of using an OTC instead of a prescription drug by multiplying the total estimated productivity loss for each ailment by the incremental efficacy, then calculated total productivity loss for each ailment by multiplying the incremental productivity loss cost for an OTC drug per case by the number who would have used OTC medications for each of the five minor ailments mentioned above in the alternative scenario. Finally, the detailed description of how we estimated the total productivity loss cost for these five minor ailments is presented in Table 2.

Estimate productivity loss cost associated with OTC drug for five minor ailments

^aProductivity loss cost = The value of an individual’s time per working day ($199.68)* absent day per year

^bIncremental efficacy = Efficacy (Rx vs. placebo) − efficacy (OTC vs. placebo)

^cIncremental productivity loss cost for OTC = Productivity loss cost* incremental efficacy

^dTotal productivity loss cost for OTC = Incremental productivity loss cost for OTC* number OF OTC request

Furthermore, we estimated the total time a patient spends at a family physician or walk-in clinic for a minor ailment would be 105 min (90 min wait time and 15 min per consultation). These estimates were based on data obtained through consultations with walk-in clinics in Saskatoon. Moreover, we estimated that 4.6 h was the average time a patient waits for care at emergency department units in Canada [38]. To calculate productivity lost due to time spent waiting for care, we multiplied the average length of time spent for GP consultations and ER visits by the number of GP appointments and ER visits in the alternative scenario and the value of an individual’s time (i.e. average wage).

Finally, we obtained the average length of time a person spends travelling to the GP clinic, ER department and pharmacy for OTC medications, from the Geographic Distribution of Physicians in Canada [39], which showed an average distance to a GP clinic, ER and pharmacy of 3.2, 24.8 and 1.6 km, respectively. Using the same travel costs per km of $0.12, we estimated the total travel cost in the alternative scenario to be $3370 per year. Finally, we include the cost of prescriptions from GPs and ERs that were paid privately (i.e. private insurance or out-of-pocket).