11.7 Urine Albumin

UK Biobank measurements for microalbumin in urine have a maximum value of 6746.5 mg/L, with many values below the measurement instrument’s lower limit of detection of 6.7 mg/L. We filter the allowable range to be under 7,000, but not 0.

#Extract urine albumin
ualb <- gp_clinical %>%
  filter(grepl(urine_albumin_codes, code, ignore.case=T)) %>%
  mutate(micro=grepl("micro", term_description, ignore.case=T)) %>%
  mutate(value = coalesce(as.numeric(value1), as.numeric(value2), as.numeric(value3))) %>%
  filter(!is.na(value)  & value != 0) %>% #& value < 500
  filter(!(value3 %in% c("0.3", "MEA001", "mg/mmol", "ml/min", "mmol/L", "MEA086",
                         "MEA096", "MEA120", "MEA142", "MEA166", "g/L", "MEA057"))) %>%  
  filter(value < 7000) %>%
  select(-value1, -value2) %>% 
  dplyr::rename(code_ualb = code, term_description_ualb = term_description,
                             ualb_mg_L = value) %>%
  distinct()

ualb %>% group_by(code_ualb, term_description_ualb) %>%
  summarize(n=n(), mean = mean(ualb_mg_L)) %>%
  arrange(desc(n)) %>% kable()

Based on the distributions, albumin values are given in mg/L, regardless of whether the term description says microalbumin or albumin.

ggplot(data=ualb, aes(x=log10(ualb_mg_L), color = term_description_ualb)) + geom_density()