Quality measurement in the shunt treatment of hydrocephalus: analysis and risk adjustment of the Revision Quotient.
OBJECT.: The Revision Quotient (RQ) has been defined as the ratio of the number of CSF shunt revisions to the number of new shunt insertions for a particular neurosurgical practice in a unit of time. The RQ has been proposed as a quality measure in the treatment of childhood hydrocephalus. The authors examined the construct validity of the RQ and explored the feasibility of risk stratification under this metric.


METHODS
The Kids' Inpatient Database for 1997, 2000, 2003, 2006, and 2009 was queried for admissions with diagnostic codes for hydrocephalus and procedural codes for CSF shunt insertion or revision. Revision quotients were calculated for hospitals that performed 12 or more shunt insertions annually. The univariate associations of hospital RQs with a variety of institutional descriptors were analyzed, and a generalized linear model of the RQ was constructed.


RESULTS
There were 12,244 admissions (34%) during which new shunts were inserted, and there were 23,349 admissions (66%) for shunt revision. Three hundred thirty-four annual RQs were calculated for 152 different hospitals. Analysis of variance in hospital RQs over the 5 years of study data supports the construct validity of the metric. The following factors were incorporated into a generalized linear model that accounted for 41% of the variance of the measured RQs: degree of pediatric specialization, proportion of initial case mix in the infant age group, and proportion with neoplastic hydrocephalus.


CONCLUSIONS
The RQ has construct validity. Risk adjustment is feasible, but the risk factors that were identified relate predominantly to patterns of patient flow through the health care system. Possible advantages of an alternative metric, the Surgical Activity Ratio, are discussed.
Nemours Neuroscience Center, A I duPont Hospital for Children, Wilmington, Delaware;
Joseph H
JH
Piatt
Christina E
CE
Freibott
D002557:Cerebrospinal Fluid Shunts / Q000592:standards / Q000706:statistics & numerical data*; D002675:Child, Preschool; D016208:Databases, Factual; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D006849:Hydrocephalus / Q000175:diagnosis / Q000601:surgery*; D007223:Infant; D008297:Male; D010343:Patient Admission / Q000706:statistics & numerical data; D012086:Reoperation; D012189:Retrospective Studies; D020379:Risk Adjustment; D012307:Risk Factors; D014481:United States / Q000453:epidemiology
CSF shunt; ETV = endoscopic third ventriculostomy; ICD-9-CM = International Classification of Diseases, Ninth Revision, Clinical Modification; KID = Kids' Inpatient Database; NACHRI = National Association of Children's Hospitals and Related Institutions; PHIS = Pediatric Health Information System; RQ = Revision Quotient; Revision Quotient; SAR = Surgical Activity Ratio; ZIP = Zone Improvement Plan; hydrocephalus; quality