Patient Preferences for Biologic and Biosimilar Osteoporosis Treatments in Colombia

Figures & data

Table 1 Attributes and Levels of the Discrete Choice Experiment

Attribute	Levels	Variable
Type of osteoporosis medicine	Original biologic medicine	BIOL
	Biosimilar medicine	BIOS^a
Length of the needle	4 mm	MM4
	6 mm	MM6
	12 mm	MM12^a
Angle of injection	At a 90-degree angle	DEG90
	At a 45-degree angle	DEG45^a
How to measure the medicine dose for each injection	You set the correct dose yourself	AUTO
	Pen sets the correct dose automatically	MANU^a
How long the medicine can be left out of the refrigerator when traveling	Never (must be kept in a cooler when traveling)	NEVR
	Can be left out of the refrigerator for up to 24 hours (1 day)	H24
	Can be left out of the refrigerator for up to 36 hours (1½ days)	H36^a

Notes: ^aThis level was omitted for model identification during estimation and recovered after estimation (as the negative sum of the included-category parameters). Standard errors were recovered using the delta method.³⁶

Figure 1 Example discrete choice experiment question (English-language version).

Table 2 Respondent Characteristics and Comparison Between Respondents Intercepted in Person and Respondents Recruited Through the Online Panel (Fisher Exact Test)

Question	Recruited Through Online Panel (N = 65)	Intercepted in Person (N = 135)	Full Sample (N = 200)	P value^a
What is your gender?
Female	44 (67.7%)	125 (92.6%)	169 (84.5%)	<0.001
Male	21 (32.3%)	10 (7.4%)	31 (15.5%)
Age (years)
N	65	134	199	<0.001
Mean (SD)	52.0 (9.2)	61.3 (12.5)	58.3 (12.3)
Median	53.0	61.0	57.0
Min, max	31, 73	27, 91	27, 91
Q1, Q3	45, 56	55, 70	51, 65
Did not answer	0	1	1
What is your marital status
Single/never married	3 (4.6%)	35 (25.9%)	38 (19.0%)	<0.001
Married/living as married/civil partnership	51 (78.5%)	58 (43.0%)	109 (54.5%)
Divorced or separated	10 (15.4%)	15 (11.1%)	25 (12.5%)
Widowed/surviving partner	1 (1.5%)	26 (19.3%)	27 (13.5%)
Other	0	1 (0.7%)	1 (0.5%)
What is the highest level of education you have completed?
Basic elementary education or less	0	45 (33.3%)	45 (22.5%)	<0.001
Secondary education	5 (7.7%)	51 (37.8%)	56 (28.0%)
Professional technical education without title	4 (6.2%)	5 (3.7%)	9 (4.5%)
Professional technical education with title	9 (13.8%)	11 (8.1%)	20 (10.0%)
Technical school	5 (7.7%)	9 (6.7%)	14 (7.0%)
5-year college degree (eg, BA, BS)	23 (35.4%)	13 (9.6%)	36 (18.0%)
Some graduate school but no degree	2 (3.1%)	1 (0.7%)	3 (1.5%)
Graduate or professional degree (eg, MBA, MS, MD, PhD)	17 (26.2%)	0	17 (8.5%)
Which of the following best describes your employment status?
Employed full time	22 (33.8%)	10 (7.4%)	32 (16.0%)	<0.001
Employed part-time	12 (18.5%)	9 (6.7%)	21 (10.5%)
Self-employed	10 (15.4%)	25 (18.5%)	35 (17.5%)
Homemaker	4 (6.2%)	60 (44.4%)	64 (32.0%)
Student	0	0	0
Retired	13 (20.0%)	23 (17.0%)	36 (18.0%)
Disabled/unable to work	0	4 (3.0%)	4 (2.0%)
Unemployed but looking for work	4 (6.2%)	3 (2.2%)	7 (3.5%)
Unemployed and not looking for work	0	1 (0.7%)	1 (0.5%)
Has used injectable medicine before^b
No	46 (70.8%)	101 (74.8%)	147 (73.5%)	0.609
Yes	19 (29.2%)	34 (25.2%)	53 (26.5%)
Are you currently taking a daily injection to treat your osteoporosis?
No	51 (78.5%)	107 (79.3%)	158 (79.0%)	1.000
Yes	14 (21.5%)	28 (20.7%)	42 (21.0%)

Notes: ^aThe P value is related to the Fisher exact test of association between respondents who were recruited through the online panel and respondents who were intercepted in person. ^bBased on the question: “What types of treatments or medicines have you ever used to treat your osteoporosis? (Please check all that apply).” Respondents were assigned to the “Has used injectable medicine before” subgroup if “Injections or infusions at a doctor’s office, hospital, or clinic” or “Injections that you give yourself at home” was selected.

Abbreviations: BA, Bachelor of Arts; BS, Bachelor of Science; Max, maximum age; MBA, Master of Business Administration; MD, Medical Doctor; min, minimum age; MS, Master of Science; PhD, Doctor of Philosophy; Q1, 25th percentile; Q3, 75th percentile; SD, standard deviation.

Table 3 Mean Coefficients from the Random Parameters Logit Model Estimates for the Full Sample (N = 200)

Attribute	Level	Estimated Parameter	95% Confidence Interval		Estimated SD
Type of medicine	Original biologic medicine	0.785	0.614	0.956	0.912
	Biosimilar medicine	−0.785	−0.956	−0.614	0.912
Needle length	4 mm	0.555	0.378	0.731	0.805
	6 mm	0.157	0.007	0.306	0.365
	12 mm	−0.711	−0.906	−0.516	1.170
Angle of injection	90-degree angle	−0.102	−0.204	0.000	0.375
	45-degree angle	0.102	0.000	0.204	0.375
How to measure the medicine dose for each injection	Pen sets the correct dose	0.501	0.367	0.634	0.594
	You set the correct dose	−0.501	−0.634	−0.367	0.594
How long medicine can be left out of the refrigerator when traveling	NEVER (must be kept in a cooler when traveling)	−0.299	−0.487	−0.112	1.012
	Can be left out of the refrigerator for up to 24 hours (1 day)	0.001	−0.141	0.143	0.446
	Can be left out of the refrigerator for up to 36 hours (1½ days)	0.299	0.096	0.502	1.458

Note: One attribute level was omitted for model identification (see Table 2) and retrieved by difference with the non-omitted levels and using the delta method to compute the standard error. All independent variables were effects coded so that the mean effect of each attribute was normalized at zero. Significance is therefore for the difference from the mean effect of the relative attribute.

Abbreviations: BIC, Bayesian information criterion; LL, loglikelihood; SD, standard deviation.

Figure 2 Conditional relative attribute importance computed for the full sample (N = 200).

Note: The graphic shows the conditional relative importance estimate for each attribute, scaled such that the attribute with the highest conditional relative importance—type of osteoporosis medicine—is set to 10, and the conditional importance of each of the other attributes is scaled relative to the conditional importance of the attribute with the highest conditional relative importance. The vertical bars surrounding each relative importance weight estimate denote the 95% confidence interval (computed using the delta method).

Figure 3 Conditional relative attribute importance comparing data from respondents recruited online and in person (N = 200).

Note: The vertical bars surrounding each relative importance weight estimate denote the 95% confidence interval (computed using the delta method).

Table 4 Descriptions of the Subgroups Analyzed (N = 200)

Subgroup Pair	Subgroup Description	Sample Size	P value
Age: 57 years or younger vs older than 57 years^a	Aged 57 years or younger	101	0.393
	Older than 57 years	98
Age: Younger than 65 years vs 65 years and older^a	Younger than 65 years	142	0.521
	Aged 65 years or older	57
Education: High school diploma or lower vs college degree or higher^b	High school diploma or lower education	144	0.002
	College degree or higher education	56
Employment: Employed or self-employed vs not employed outside the home^c	Full-time, part-time, or self-employed	88	0.023
	Not employed outside the home	112
Marital status: Married vs others^d	Married	109	0.809
	Other civil status	91
Fracture experience^e	Has never experienced fracture(s)	170	0.374
	Has previously experienced fracture(s)	30
Injection experience^f	Has used injectable medicine before	53	0.240
	Has never used injectable medicine	147

Notes: ^aOne respondent did not provide the year they were born, so they are not included in the dummy-coded variable. ^bThis subgroup was created based on answers to the question, “What is the highest level of education you have completed?” Respondents were assigned to the “High school diploma or lower education” subgroup if they answered either “Basic elementary education or less,” “Secondary education,” “Professional technical education without title,” “Professional technical education with title,” or “Technical school”; respondents were assigned to the “College degree or higher education” subgroup if they answered “5-year college degree,” “Some graduate school but no degree,” or “Graduate degree.” ^cThis subgroup was created based on answers to the question, “Which of the following best describes your employment status?” Respondents were assigned to the “Full-time, part-time, or self-employed” subgroup if they answered either “Employed full-time,” “Employed part-time,” or “Self-employed”; respondents were assigned to the “Not employed outside the home” subgroup if they answered “Homemaker,” “Student,” “Retired,” “Disabled/unable to work,” “Unemployed but looking for work,” or “Unemployed and not looking for work.” ^dThis subgroup was created based on answers to the question, “What is your marital status?” Respondents were assigned to the “Married” subgroup if they answered “Married/living as married/civil partnership”; respondents were assigned to the “Other civil status” subgroup if they answered “Single/never married,” “Divorced or separated,” “Widowed/surviving partner,” or “Other.” ^eThis subgroup was created based on answers to the question, “Which of the following symptoms of osteoporosis have you ever experienced? (Please check all that apply).” Respondents were assigned to the “Has previously experienced fracture(s)” subgroup if “Fracture of the spine, wrist, forearm, or hip” was selected. ^fThis subgroup was created based on answers to the question, “What types of treatments or medicines have you ever used to treat your osteoporosis? (Please check all that apply).” Respondents were assigned to the “Has used injectable medicine before” subgroup if “Injections or infusions at a doctor’s office, hospital, or clinic.”

Figure 4 Conditional relative attribute importance for the subgroup analysis based on employment status (N = 200).

Note: The vertical bars surrounding each relative importance weight estimate denote the 95% confidence interval (computed using the delta method).

Figure 5 Conditional relative attribute importance for the subgroup analysis based on level of education (N = 200).

Note: The vertical bars surrounding each relative importance weight estimate denote the 95% confidence interval (computed using the delta method).

Hensher DA, Rose JM, Greene WH. Applied Choice Analysis. Cambridge (UK): Cambridge University Press; 2005.

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