Table 1

Content of the parent and adolescent surveys (parts A and B)

Domain	Concept		Source of items and scales	Parent survey (part A)	Adolescent survey (part B)
(1) Utilisation of paediatric primary care services	(1.A) Deferral and cancellation of different types of paediatric primary care services		Modified from McDonnell et al51	X
(2) Utilisation of telemedical services	(2.A) Utilisation of different types of telemedical services before and during the COVID-19 pandemic		^*	X	X
(3) Correlates of paediatric primary care utilisation	(3.A) Concerns about visiting the paediatric primary care practice (eg, fear of infection in the paediatric primary care practice)		Modified from McDonnell et al51as well as free-text question	X	X
	(3.B) Sense of security in paediatric primary care practice		^*	X	X
	(3.C) Perceived implementation of infection control measures in paediatric primary care practice		^*	X
	(3.D) Personal experiences related to the pandemic (eg, member of risk group in household, personal experience with quarantine)		^*	X
	(3.E) Fear of child’s infection with COVID-19		Modified from McDonnell et al51	X	X
	(3.F) Reasons for not using telemedical services (eg, limited internet access, lack of technical equipment)		^*	X
(4) Leverage points for strengthening paediatric primary care	(4.A) Possibilities to facilitate lower risk consultations at paediatric primary care practices during the COVID-19 pandemic		Free-text question	X	X
(5) Aspects of child health	(5.A) Chronic conditions of children†		CSHCN screener (adequate internal consistency (Cronbach’s alpha 0.76); precise measurement among children experiencing elevated health-condition-complexity trait levels)43	X
(5) Aspects of child health	(5.B) Parent-reported/child-reported general child health status		KIGGS baseline study52	X	X
(6) Aspects of parental health	(6.A) General health status		A single item from the Short Form 36 Health Survey Questionnaire53	X
	(6.B) Parental stress†		Perceived Stress Scale-4 (PSS-4; adequate internal consistency (Cronbach’s alpha 0.60);54 construct validity was shown for the PSS-10, which the PSS-4 is based on, in a German population55)	X
	(6.C) Perceived parental depression and anxiety†‡56		Patient Health Questionnaire-4 (scale to screen for symptoms of depression and anxiety; good internal consistency (Cronbach’s alpha 0.82); convergent validity was shown in a German population)42	X
(7) Sociodemographic characteristics	Child	(7 .A) Age‡57	In years	X
		(7.B) Gender	Female/male	X
		(7 .C) Migration background†‡58	Migration background if either one parent or the child was not born as German citizen	X
	Parent	(7.D) Age	< 20, 20–29, 30–39, 40–49, 50–59, ≥ 60 years	X
		(7.E) Gender	Female/male	X
		(7 .F) Educational attainment†‡59	KIGGS baseline study;52 based on the ISCED-201160	X
		(7 .G) Single parent†‡61	Single parent/nuclear family	X

The English version of all items developed for this study and all adapted items are provided in the online supplemental appendix 1. A subset of items of the parent survey are also included in the adolescent survey.
*Items developed by the research team.
†Family-level factors of vulnerability potentially driving adverse changes in service utilisation.
‡Potential confounders of the association between family-level and area-level deprivation and service utilisation.
CSHCN, children with special healthcare needs; ISCED, International Standard Classification of Education; KIGGS, German Health Interview and Examination Survey for Children and Adolescents (Studie zur Gesundheit von Kindern und Jugendlichen in Deutschland).