الفهرس 
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Abstract
6.1.1. Introduction
Patient preferences for their medications strongly affect their medication adherence; one of the areas of significant research interest is the preferences for branded and generic drugs. Generic drugs are bioequivalent to branded originator drugs. They should share the same strengths, dosage form, efficacy, and safety as the original versions; however, they are sold at markedly reduced prices that can increase the efficiency of health insurance systems.
Most of the research on generic-vs-branded drugs studied the public knowledge, perceptions, and acceptability of generic substitution. We found few studies that focused on the preferences of patient populations like those suffering from severe illnesses. Coronary heart diseases (CHD) are among the leading causes of death worldwide. This study aims to assess the patients’ preferences for generic CHD drugs at the Alexandria Health Insurance Clinic. Specifically, we want to determine the relative patient preferences across the different classes of their medications.
6.1.2. Methods
Study design: a cross-sectional study using a face-to-face survey.
Setting: Alexandria Health Insurance Clinic.
Population: CHD patients who dispense the monthly refills of their CHD prescriptions that include at least Aspirin, a Beta blocker, a Statin, and a Renin-Angiotensin-Aldosterone system (RAAS) blocker (either an Angiotensin-converting enzyme inhibitor or an Angiotensin receptor blocker).
Sample size: the minimum required sample size is 100 respondents. It was calculated by Conjoint.ly, which is specialized computer software for conjoint analyses.
Survey: It consists of three parts:
1. A sociodemographic survey collected the participants’ age, sex, education, occupation, and income levels.
2. A direct patients’ satisfaction survey explored the patients’ perceptions about the importance of their CHD drugs, their satisfaction with their dispensed generic CHD drugs, and their drivers for brand inclination.
3. A discrete choice experiment is a choice-based conjoint analysis where the patients are presented with ten choice tasks. Each task includes their current (status quo) combination of dispensed generic and branded drugs in addition to 2 hypothetical priced alternatives that consist of different combinations of generic and branded CHD drugs. The patients are asked to choose the alternative they prefer the most from each task. The experimental design of the choice tasks was constructed using Conjoint.ly.
Statistical Analyses: performed using R software version 4.1.1. and consist of three parts:
1. Sociodemographic characteristics and the direct patients’ satisfaction survey analyses.
2. A Discrete choice experiment analysis provided the relative preference weights of the brands of the four classes. Those weights are used to calculate the attribute partworths and the willingness to pay values for each class’s brand.
3. Subgroup analyses based on sociodemographic characteristics examine the effect of age, education, and income on the choice modelling.
6.1.3. Results
1. Sociodemographic characteristics and the direct patients’ satisfaction survey analyses results: The results for each question are summarized as follows:
• Sociodemographic characteristics: We completed the survey with 208 CHD patients during a three-month period from July 2021 to October 2021, whose summary of characteristics is as follows:
o Mean age (± SD): 67 (± 8) years
o Sex: 163 males (78%)
o Occupation: 86% were non-working pensioners
o Education: 94 patients had less than intermediate education and 114 with at least intermediate education.
o Income: 76 patients reported they were in debt, while the remaining 132 patients have incomes that at least meet their routine expenses.
• Perceptions about the CHD drugs’ importance: Most patients believed that all their prescribed medications are important for their condition. No significant differences or differential weighting could be observed.
• Patients’ acceptance of using the dispensed generic CHD drugs: Fifty-nine patients (28%) were fully satisfied with the generics. The overall satisfaction with the generic drugs for each class were: Aldosterone antagonist; 62%, Aspirin; 52%, Beta-blocker; 43%, Calcium channel blocker; 25%, Nitrate; 55%, P2Y12 inhibitors; 0%, RAAS blocker; 39%, Statin; 48%, and Trimetazidine; 45%.
• Drivers for brand inclination: Among the brand inclined respondents, the percentages of patients who reported that they tried the generic and found it not effective for each class were: Aldosterone antagonist; 80%, Aspirin; 55%, Beta-blocker; 55%, Calcium channel blocker; 46%, Nitrate; 64%, P2Y12 inhibitors; 23%, RAAS blocker; 53%, Statin; 59%, and Trimetazidine; 38%.
2. Discrete choice experiment results: The primary analysis was performed first on the whole sample (WS) and then repeated on the subset of the 149 dissatisfied patients, and the subgroup analyses were performed on the whole sample:
• Preference weights: all weights of the brands were found to be significant in both models. Positive weights mean more preference for the brands, while negative weights mean more preference for the generic. The order of the respondents’ preferences for the different classes in the WS (with the 95% CI) is: 1- RAAS blocker; 0.512 (0.428 to 0.596) , 2- Beta-blocker; 0.167 (0.088 to 0.246), 3- Statin; -0.185 (-0.279 to -0.090), and 4- Aspirin; -0.687 (-0.768 to -0.606), while for the dissatisfied subset we found the same order with higher weights and the Statin weight turned positive: 1- RAAS blocker; 1.143 (1.039 to 1.247), 2- Beta-blocker; 0.724 (0.630 to 0.818), 3- Statin; 0.403 (0.287 to 0.518), and 4- Aspirin; -0.338 (-0.431 to -0.245). The price weight was adjusted by multiplication by 364 to account for the highest price presented to the respondents. It was found to have the highest impact on utility with adjusted weight in WS -2.081 and -3.251 in the dissatisfied subset.
• Relative importance: the order of relative importance in the WS analysis was found: 1- Aspirin (18.9%), 2- RAAS blocker (14.1%), 3- Statin (5.1%), and 4- Beta-blocker (4.6%) while in the dissatisfied subset’s analysis the Aspirin came last and the order was: 1- RAAS blocker (19.5%), 2- Beta-blocker (12.4%), 3- Statin (6.9%), and 4- Aspirin (5.8%). The price had the highest relative importance in affecting the utilities in both analyses: 57.3% in WS and 55.5% in the dissatisfied subset’s analyses.
• Willingness to pay (WTP): The WTP values in the WS analysis were found in the following order: 1- RAAS blocker; 90 EGP, 2- Beta-blocker; 29 EGP, 3- Statin; -32 EGP, and 4- Aspirin; -120 EGP. In the dissatisfied subset’s analysis, the order was the same, but the Statin WTP turned from negative (means less preference of the brand) to positive, and all the values increased: 1- RAAS blocker; 128 EGP, 2- Beta-blocker; 81 EGP, 3- Statin; 45 EGP, and 4- Aspirin; -38 EGP.
• Subgroup analyses: We found significant effects of age, education, and income on the patients’ preferences, and the main differences were as follows:
• Age: The statin brand’s weight was not significant, and the class had the minor relative importance (4%) in those below 68 years, while the Beta-blocker brand weight was not significant, and the class had minor importance (2.1%) in those above 68 years.
• Education: In the respondents with less than intermediate education, the Beta-blocker and Statin brands’ weights were not significant, and their classes had markedly low importance scores: 0.6% and 0.7%, respectively.
• Income: The income significantly affected the magnitude but not the order of relative importance scores where those in debt had higher importance for the price at the expense of the other attributes.