Although, the study has several limitations that merit
caution. First, patients who may have higher education and
better medical compliance or doctor–patient interaction could
have an effect. However, it is difficult to control these situations.
Second, the NHI claim database lacks detailed biophysiological
measures; thus, this study was unable to investigate
the intermediate measures, such as the levels of HbA1c, BP, and
other CKD-specific examinations. Third, several patients in
both interventions may not have had sufficient time of interventions,
which is likely to cause an underestimate of the P4P
intervention effects. Fifth, the declination of renal function was
higher in this population (8.38% of the diabetic nephropathy
patients developed late CKD or ESRD within 2 years of followup)
as opposed to that of Western population. The generalizability
of the findings to other populations is suggested to be
cautious. Finally, residual effects of the confounding variables
may still exist under multivariable models. As such, patient’s
medical seeking behavior and adherence to providers were not
able to be examined in this national health claim database.