Monday, September 3, 2012
Hawaii and Population Management
You're in clinic and have just seen a 69 year old man with a longstanding history of hypertension. He has been referred by his internist to nephrology for an eGFR of 51 ml/min/m2. He has a bland urinalysis, an unremarkable renal ultrasound and a urine microalbumin to creatinine ratio of 20 mg/g. The patient and his internist have his blood pressure under good control and have addressed other modifiable cardiovascular risk factors.
You've seen this case a million times, right?
How about this one...
You are called to the Emergency Department to see a 51 year old morbidly obese female with a longstanding history of type 2 diabetes and hypertension who has just presented after several weeks of fatigue and pruritis now accompanied by nausea and vomiting. Her labs show anemia, hyperphosphatemia, hypocalcemia, acidosis, hyperkalemia and marked uremia. A subsequent renal ultrasound shows small echogenic kidneys. During the hospitalization she begins maintenance dialysis with a tunneled catheter with a plan for her to continue in-center dialysis 3 times a week on discharge.
The patient had never seen a nephrologist prior to her hospitalization.
Sadly, this case is familiar too, right?
The two cases above highlight the over and underutilization of nephrology resources in our current care system. Individuals like the 69 year old man in the first scenario gain little value from a visit to the nephrologist. The risk of him every progressing to need for renal replacement is incredibly low and the services which he needs (CV risk factor control) are competently provided by his internist.
In contrast, the woman in the second scenario is representative of some 40% of patients who start dialysis today who have never seen a nephrologist prior to beginning renal replacement. Only 25% have seen a nephrologist for at least year prior to ESRD. Patients like the woman in the scenario would clearly benefit from disease progression delay strategies, modality education (home, center, transplant) along with appropriate preemptive dialysis access placement (AVF, AVG or PD catheter - depending on modality choice) - all services that nephrology provides.
In light of the above it's encouraging to see the ongoing efforts of organizations like Kaiser Permanente (KP) Hawaii who recently published more results from their experience with proactive population management.
In their system, an electronic tool sweeps the electronic medical records of the entire KP Hawaii population monthly for two basic parameters: eGFR and proteinuria. Patients are divided into high and low risk groups for progression to need for renal replacement. A nephrologist reviews the list regularly and proactively reaches out to primary care physicians to bring unrefereed high risk patients into nephrology care. The patients at lower risk remain or return to primary care with remote physician-to-physician mentoring from the nephrologist.
In an initial report, their system was associated with an increase in the fraction of patients starting dialysis with a mature AVF (18% vs 36%), the fraction beginning dialysis as outpatients (35% vs 56%) and a higher proportion of new referrals consisting of high risk patients (16% vs 35%) and a lower proportion of patients at low risk (50% vs 30%). There was a nice shift towards dedicating more nephrology new referral effort towards individuals who theoretically derive the most benefit from it with a downstream improvement in dialysis specific outcomes. As this was a pre- to post- intervention comparison there are the usual caveats about whether there was a change in the population or some other concurrent change that contributed to the shifts in outcome.
In the followup report a smaller portion of patients showed progressive CKD when they were matched by propensity score to a historic cohort. Although this may have been in part due to improvements in management of blood pressure and proteinuria in the primary care setting through remote nephrology mentoring I have to imagine that the internal blood pressure goal and education initiatives mentioned in the discussion played a substantial role.
Despite the weaknesses of the above studies the idea of proactive risk segmentation of a CKD population with appropriate application of nephrology resources is a highly appealing one. We have only just scratched the surface of how to incorporate information technology into medical practice and efforts like the above to leverage the data contained within the electronic medical record are a way forward.