Consumer satisfaction with OTC drugs: an analysis using the confirmation/disconfirmation model

A Systematic Review of Patient-Reported Satisfaction with Oral Medication Therapy in Patients with Type 2 Diabetes

OBJECTIVE

To provide a comprehensive comparative evaluation of the psychometric properties of satisfaction with medication surveys used for patients with type 2 diabetes (T2D) in clinical trials.

METHODS

Instruments identified through a comprehensive literature search were evaluated based on the following criteria: disease specificity, peer-reviewed publication (administered in English in patients with T2D on oral therapy), and availability of psychometric properties.

RESULTS

Eight instruments (Diabetes Medication Satisfaction [DiabMedSat]; Diabetes Treatment Satisfaction Questionnaire, status version [DTSQs]; Diabetes Medication System Rating Questionnaire [DMSRQ]; Diabetes Medication System Rating Questionnaire-Short Form [DMSRQ-SF]; Diabetes Tablet Treatment Questionnaire [DTTQ]; Perceptions About Medications for Diabetes [PAM-D]; Satisfaction with Oral Anti-Diabetic Agent Scale [SOADAS]; Diabetes Medication Satisfaction Tool [DMSAT]) were included in the study based on the predefined inclusion criteria. Seven of the instruments (all but DTTQ) utilized patients in the survey development process. All eight instruments could be completed within 15 minutes and thus were considered practical. DiabMedSat, DMSRQ, and DMSRQ-SF encompassed broader aspects of satisfaction than the other instruments. All of the instruments reviewed showed substantial floor or ceiling effects, except for DMSAT and DiabMedSat, without complete information. The DMSRQ and DMSRQ-SF each satisfied the criteria for reliability. DiabMedSat, DTSQs, DMSRQ, DMSRQ-SF, SOADAS, and DMSAT showed favorable convergent and discriminant validity. All of the instruments except DTTQ were determined to satisfactorily meet the criteria of responsiveness.

CONCLUSION

Although it is up to researchers to decide which instrument to use according to the resources available and specific aims of their studies, DMSRQ and DSMRQ-SF were recommended based on the evaluative criteria employed in this study.

Expectations do not Influence the Response to Phosphosdiesterase Type 5 Inhibitor Therapy for Erectile Dysfunction

It has been reported that patients frequently discontinue treatment for erectile dysfunction (ED) with phosphodiesterase type 5 inhibitors (PDE5Is) despite apparently good therapeutic results. Because expectations have been shown to affect patients’ appraisals of many drugs, the purpose of this study was to determine whether expectations affected the therapeutic response to PDE5Is in men with apparent psychogenic ED. An unvalidated questionnaire was used to collect data on expectations in 80 men commencing PDE5I therapy, and after three and six months of treatment. At the same time, subjects completed the International Index of Erectile Function (IIEF), the Sexual Excitation/Inhibition Scale (SIS/SES) and Beck’s Depression Inventory (BDI). No evidence of an effect on expectations on changes in IIEF or BDI scores could be identified. Although changes in IIEF, and BDI scores from recruitment to three months were indicative of improved sexual function and less depression, scores for most items on the expectations scale decreased, suggesting that expectations were not being met. The items for which scores decreased were the expectation to be prescribed a drug, that the drug would restore the sexual function to normal, would work within 30 minutes of administration, improve patients confidence to engage in sexual activity, and that the medication was the best treatment for ED across the three data collection points. The findings of this study indicate that improvements in erectile function did not translate into changes in medication expectations that suggested user satisfaction.

Patients' Preferences for Generic and Branded Over-the-Counter Medicines: An Adaptive Conjoint Analysis Approach

BACKGROUND

: Despite increased use of generic medicines, little is known about either the attitudes of patients towards them or the decision-making process surrounding them. Young adults use over-the-counter (OTC) analgesics relatively often.

OBJECTIVE

: To assess the preferences of patients for generic and branded OTC pain medicines, to identify clusters with different preference structures, and to estimate the price elasticity of a generic alternative among university students.

METHODS

: Finnish university students (n = 256; students in courses at the Helsinki School of Economics) responded to an adaptive conjoint analysis (ACA) questionnaire on the choice between branded and generic OTC ibuprofen products. Product attributes of price, brand, onset time of effect, place of purchase and source of information were included in the questionnaire on the basis of the literature, a focus group and a previous pilot study. Several socioeconomic and health behavior descriptors were employed. Individual-level utility functions were estimated, preference clusters were identified, and the price elasticity of the generic medicine was assessed.

RESULTS

: Five clusters with characteristic individual-level preferences and price elasticity but few differences in socioeconomic background were detected. Approximately half of the respondents were strongly price sensitive while the others had other preferences such as brand or an opportunity to buy the medicine at a pharmacy or to have a physician or a pharmacist as an information source.

CONCLUSION

: The study provided new information on the concomitant effects of brand, price and other essential product attributes on the choice by patients between branded and generic medicines.

WITHDRAWN: Nasal decongestants for the common cold

BACKGROUND

The common cold is a major and recurrent cause of morbidity, on average affecting children and adults two or more times each year. Nasal congestion is its commonest symptom and many therapies are marketed for its relief. There is no meta-analysis of controlled clinical trials on the effects of nasal decongestants in the common cold.

OBJECTIVES

To assess the efficacy of nasal decongestants at reducing the symptom of nasal congestion in adults and children with the common cold and to identify possible adverse effects associated with their use.

SEARCH STRATEGY

In this updated review in 2006, the following databases were searched: the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2006, issue 3); MEDLINE (January 1996 to September 2006); OLDMEDLINE (1951 to 1965); EMBASE (1980 to Week 36, 2006). We contacted known principal investigators and pharmaceutical companies.

SELECTION CRITERIA

Randomised, placebo controlled trials of single-active oral and topical nasal decongestants in adults and children suffering from common cold.

DATA COLLECTION AND ANALYSIS

Two review authors (DT, GJL) independently extracted data. All outcomes variables were continuous. Subjective outcomes were normalised to a common scale and a weighted mean difference (WMD) was calculated. A standardised mean difference (SMD) was calculated for the objective outcomes.

MAIN RESULTS

Seven studies in adults, but none in children, fitted all inclusion criteria. There was a small but statistically significant 6% decrease in subjective symptoms after a single dose of decongestant compared with placebo. This was supported by a significant decrease in nasal airways resistance. With repeated doses, nasal decongestants produce a very small statistical benefit of 4% over three to five days, again supported by a decrease in nasal airways resistance. Two studies provided safety data for this meta-analysis, showing a relatively small number of adverse events and only a small increased risk of insomnia with pseudoephedrine compared to placebo.

AUTHORS' CONCLUSIONS

A single oral dose of nasal decongestant in the common cold is modestly effective for the short term relief of congestion in adults, and these drugs also provide benefit in some individuals after regular use over three to five days. Adverse events in adults are rare and mild. There is insufficient data on the use of these medications in children and therefore they are not recommended for use in children younger than 12 years of age with the common cold.

Nasal decongestants for the common cold

BACKGROUND

The common cold is a major and recurrent cause of morbidity, on average affecting children and adults two or more times each year. Nasal congestion is its commonest symptom and many therapies are marketed for its relief. There is no meta-analysis of controlled clinical trials on the effects of nasal decongestants in the common cold.

OBJECTIVES

To assess the efficacy of nasal decongestants at reducing the symptom of nasal congestion in adults and children with the common cold and to identify possible adverse effects associated with their use.

SEARCH STRATEGY

In this updated review in 2006, the following databases were searched: the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 3, 2006); MEDLINE (January 1996 to September 2006); OLDMEDLINE (1951 to 1965); EMBASE (1980 to Week 36, 2006). We contacted known principal investigators and pharmaceutical companies.

SELECTION CRITERIA

Randomised, placebo controlled trials of single-active oral and topical nasal decongestants in adults and children suffering from common cold.

DATA COLLECTION AND ANALYSIS

Two review authors (DT and GJL) independently extracted data. All outcomes variables were continuous. Subjective outcomes were normalised to a common scale and a weighted mean difference (WMD) was calculated. A standardised mean difference (SMD) was calculated for the objective outcomes.

MAIN RESULTS

Seven studies in adults, but none in children, fitted all inclusion criteria. There was a small but statistically significant 6% decrease in subjective symptoms after a single dose of decongestant compared with placebo. This was supported by a significant decrease in nasal airways resistance. With repeated doses, nasal decongestants produce a very small statistical benefit of 4% over three to five days, again supported by a decrease in nasal airways resistance. Two studies provided safety data for this meta-analysis, showing a relatively small number of adverse events and only a small increased risk of insomnia with pseudoephedrine compared to placebo.

AUTHORS' CONCLUSIONS

A single oral dose of nasal decongestant in the common cold is modestly effective for the short term relief of congestion in adults, and these drugs also provide benefit in some individuals after regular use over three to five days. Adverse events in adults are rare and mild. There is insufficient data on the use of these medications in children and therefore they are not recommended for use in children younger than 12 years of age with the common cold.

Hierarchical construct validity of the treatment satisfaction questionnaire for medication (TSQM version II) among outpatient pharmacy consumers

OBJECTIVES

The objectives of this study were twofold: 1) to evaluate the construct validity of the Treatment Satisfaction Questionnaire for Medication (TSQM v. II) using structural equation modeling (SEM); and 2) to assess its concurrent validity using medication adherence criteria.

METHODS

Pharmacy patients filling a new medication prescription (n = 342) were recruited from 14 Michigan pharmacies to participate in a 4-week treatment satisfaction study. The TSQM v. II was tested for model fit against an established theoretical model (the Decisional Balance Model of Treatment Satisfaction) using hierarchical confirmatory factor analysis (HCFA). Regression and discriminant analytic models were used to examine the criterion-related validity of the measure.

RESULTS

An exploratory factor analysis, used for TSQM v. II item reduction, revealed a strongly dimensional instrument (Effectiveness, Side Effects, and Convenience) and explained 88% of total pooled variance. Results of an HCFA using the final TSQM v. II items suggested a good model fit with the data (P > 0.54). In support of concurrent validity, the TSQM scales explained between 9% and 20% of the variance in dosing adherence and 60% of the variance in the likelihood of future use. Discriminant analysis demonstrated the superior classification power of the hierarchical model of treatment satisfaction over the discrete attribute model when predicting medication discontinuation.

CONCLUSIONS

The TSQM v. II has equivalent measurement characteristics as the TSQM v. I, yet uses four fewer items and more consistent wording. The value of the Decisional Balance Model for estimation of dosing adherence and medication persistence over time is discussed.