Table 3

Operationalisation of variables calculated from the included variables in the HF registry

Social economic statusScore for socioeconomic status (including degree of education, wealth and employment history (WOA)) by zip code area according to the 2019 data from the Social Cultural Planning Agency; divided into quartiles or quintiles, where 1 is a low SES-WOA score.
Body mass indexDerived from weight in kilogram and length in centimetres, calculated as weight/(length×length).
CKDBased on the cut-off values of eGFR calculated from serum creatinine level (collected by the HF registry). The HF registry calculates eGFR as the following:
Male: (175×(creatinine level/88.4)ˆ−1.154)×(age Tnˆ−0.203)
Female: (175×(creatinine level/88.4)ˆ−1.154)×(age Tnˆ−0.203)×0.742
CKD=eGFR ≥60 mL/min/1.73 m2
No CKD=eGFR <60 mL/min/1.73 m2
DepressionHealth-related QoL derived from the SF-12 or SF-36 questionnaire.
Scoring: 0–100; the lower the score, the more disability; the higher the score, the less disability; that is, a score of 0 is equivalent to maximum disability and a score of 100 is equivalent to no disability.
  • CKD, chronic kidney disease; eGFR, estimated glomerular filtration rate; HF, heart failure; QoL, quality of life; SES, social economic status; SF-12, 12-item short form health survey; SF-36, 36-item short form health survey; WOA, wealth, educational level and employment history (in Dutch: welvaart, opleidingsniveau, arbeidsverleden).