**3.3 Facility-level factors**

Pisoni and colleagues studied facility-level risk factors for haemoglobin variability in 26,510 haemoglobin patients from 930 facilities in 12 countries using the DOPPS data (Pisoni et al., 2011). Haemoglobin variability was not associated with the number of haemodialysis patients per facility. However, larger differences in mean facility-level haemoglobin standard deviation were seen between countries. The mean age was nearly 2 years younger in the highest quartile of facility-level haemoglobin standard deviation than the lowest quartile. The investigators found that BMI, neutrophil count, and prevalence of psychiatric disorders and hepatitis C were higher in facilities with higher facility-level haemoglobin standard deviation. They also observed a positive association between haemoglobin variability and increased proportion of patients in a facility with parathyroid hormone level >450 pg/mL. Furthermore, the investigators reported a strong correlation (*r* =0.56) between facility-level haemoglobin standard deviation and within-patient haemoglobin standard deviation. These findings suggest that the results of this facility-level study could be generalised to an individual patient.
