Study Population

We used data from the Stockholm CREAtinine Measurements (SCREAM) Project (2,19). Briefly, the SCREAM Project is a health care utilization cohort from the region of Stockholm, Sweden, and it includes all residents who undertook at least one measurement of serum creatinine in ambulatory or hospital care during 2006–2011. Creatinine and other laboratory data were linked with regional and national administrative databases for information on health care utilization, dispensed drugs, validated RRT end points, and follow-up for death, with virtually no or minimal loss to follow-up. Given the commonness of creatinine testing, the SCREAM Project captured 66% of the complete population census of the region, including >75% of individuals above the age of 45 years old (19). For this study, index date was determined by the first available serum creatinine measurement of any adult (>18 years old) (Supplemental Figure 1). Exclusion criteria were creatinine measurement during a hospital stay, pregnancy (defined by the presence of an International Classification of Disease, 10th Revision, Clinical Modification [ICD-10] code among Z321, Z33–Z38, and any O code in the preceding 6 months), presence of chronic infections (including HIV; ICD-10 codes B15–B19, B20–B24, and A15–A19), or undergoing RRT (dialysis or history of kidney transplantation as ascertained by linkage with the Swedish Renal Registry (http://www.medscinet.net/snr/) (Supplemental Material). To avoid selecting creatinine values that may be determined by preexisting infections, we excluded serum creatinine measurements with a diagnosis of infection during the preceding 3 months (definitions of infection are in Supplemental Table 1).