Table 3.

Descriptive statistics of control variables and variables to stratify physicians by active ingredient, 2013.

Drug (n = Number of Physician–Quarter Combinations)	Statistic	Erythropoesis-Stimulating Agents (n = 10,948)		Filgrastim (n = 1516)		Somatropin (n = 3193)		Total (n = 19,707)
Number of patients in practice receiving biologic drug	mean	54.17		19.25		23.47		37.35
	(s.d.)	(57.32)		(23.16)		(42.08)		(49.51)
Share of patients receiving biologic drug in practice	mean	0.03		0.01		0.01		0.02
	(s.d.)	(0.07)		(0.03)		(0.02)		(0.05)
Patient age (biologic patients)	mean	70.45		59.53		25.42		59.77
	(s.d.)	(8.35)		(10.94)		(18.79)		(17.63)
Comorbidity index of biologic patients	mean	17.26		13.54		9.06		14.54
	(s.d.)	(3.60)		(3.14)		(3.85)		(4.75)
Share of male individuals of biologic patients	mean	0.50		0.39		0.57		0.49
	(s.d.)	(0.23)		(0.28)		(0.26)		(0.25)
Share of individuals older than 65 years of age of biologic patients	mean	0.74		0.47		0.07		0.51
	(s.d.)	(0.23)		(0.25)		(0.19)		(0.36)
Total number of patients in practice	mean	1362.51		1704.44		1939.04		1584.65
	(s.d.)	(1161.10)		(1493.27)		(2202.65)		(1449.43)
Price per defined daily dose of packages prescribed by physician (biologics incl. biosimilars)	mean	10.98		175.21		53.24		45.84
	(s.d.)	(3.13)		(94.88)		(18.22)		(70.07)
Average household income in region of practice in 1000 EUR	mean	1699.60		1695.37		1702.37		1702.10
	(s.d.)	(173.48)		(177.99)		(167.78)		(173.82)
		N	%	N	%	N	%	N	%
Type of practice
Solo practice		4206	38.42	1059	69.85	1748	54.74	9360	47.5
Group practice		6742	61.58	457	30.15	1445	45.26	10,347	52.5
Area
Metropolitan		5409	49.41	814	53.69	1637	51.27	9864	50.05
Urbanized		4129	37.71	575	37.93	1165	36.49	7343	37.26
Rural		1410	12.88	127	8.38	391	12.25	2500	12.69
Specialist status
General practitioner		2470	22.56	293	19.33	482	15.1	3637	18.46
Specialist		8478	77.44	1223	80.67	2711	84.9	16,070	81.54