Spatio-temporal Clusters of New Psychotropic Medications among Michigan Children Insured by Medicaid Rob Penfold, PhD Associate Investigator Group Health Research Institute penfold.r@ghc.org
Introduction • Background • Socio-political and practice environment • Local culture • Evidence-based practice & Practice-based evidence • Spatio-temporal Surveillance • Tool for knowledge translation and educational outreach • Prescribing of psychotropic medications in Michigan • Growth in prescribing • Relationship to commercial detailing • Implications for educational outreach visits
Acknowledgments Kelly Kelleher, MD MPH Center for Innovation in Pediatric Practice Nationwide Children’s Hospital, Columbus, OH Kathleen Pajer, MD Center for Biobehavioral Health, NCH Brandon Strange, MD Division of Child Psychiatry, NCH Wei Wang, MSc Center for Innovation in Pediatric Practice, NCH
Engaging Providers in Practice Change • Academic detailing, counter detailing • Most effective approach for changing behavior (in the “wild”) but expensive • P&T committees • Formulary restrictions, prior authorization, quantity limits, step therapy, concurrent medication caps, drug utilization review • Can be targeted • Not all physicians need face-to-face interventions • e.g. Trepka (2005) geographically defined intervention • Must monitor behavior/performance
Surveillance ↔ Outreach “As hospitals, health maintenance organizations, and other health care organizations continue to develop computerized systems to track resource utilization on a physician-specific basis, it will become increasingly practical to identify physicians with particular utilization problems and present them with focused educational interventions . . . Surveillance and feedback of this sort is another approach that may work best in certain settings with established lines of authority (e.g., teaching hospitals and staff model health maintenance organizations)” (Soumerai and Avorn, 1990, p552).
Spatio-temporal Surveillance • Spatial Scan Statistic • Identify communities, locations, or practice networks that change behavior first/early • Focus resources both spatially and temporally • Use cluster characteristics to guide interventions
1 R03 MH077573-01A1 • Spatio-temporal Diffusion of Psychotropic Medications to Rural Children • Central hypothesis: the location and timing of prescribing for psychotropic medications depends on collegial interaction during the referral process • Hypothesis 2: the ratio of mental health specialists to primary care physicians in a county is associated with the rate of prescribing.
First Step • Hypothesis 1: • Do prescriptions tend to cluster in a cross section of new psychotropic medications? • Hypothesis 2: • Related to patient characteristics? • Related to access to psychiatrists?
Why Psychotropic Medications? • Rapid increase in utilization • Low barriers to prescribing • Expensive • Cost/benefit debate • Effectiveness, safety, side effects, non-adherence, clinical appropriateness • Preferred drug list and prior authorization strategies • Preliminary results regarding olanzapine
Why Children? • Weak evidence base regarding safety and efficacy of these meds in young children • No (legal) explicit data from Pharmaceutical reps regarding children • Collegial interaction likely to be a stronger influence • Transmission of practice-based evidence • Utilization versus prescribing • Who is doing the “adopting”
Why Michigan? • First preferred drug list in 2002 (MPPL) • National attention • Implemented by several states • Prior authorization in 2002 • Representative vis-à-vis utilization and need for MH services
Methods
Methods - Data • Medicaid Analytic Extract (MAX) from Centers for Medicare & Medicaid Services • Personal summary file (age, sex, race, ZIP, SSN) • Prescriptions file (NDC, date, Rx-ing MD) • Michigan between Jan. 2000 and Dec. 2003 • Selected all individuals aged less than 21 years
Data cont’d • Provider enrolment file from Michigan • Physician ID number, specialty, ZIP • Rural-urban commuting area codes by ZIP • Area resource file by county • Verispan Inc. - commercial detailing effort • Personal selling audit • Hospital selling audit • Physician meetings and events audit
Study Medications Medication FDA date Children aripiprazole (Abilify) 11/15/2002 13,076 atomoxetine (Straterra) 11/26/2002 14,087 escitalopram (Lexapro) 8/15/2002 15,570 ziprasidone (Geodon) 2/5/2001 18,302 methylphenidate OROS (Concerta) 8/1/2000 51,303
Control Medications • Matched by class Atomoxetine (Strattera) aripiprazole (Abilify) escitalopram methylphenidate oros (Lexapro) ziprasidone (Geodon) (Concerta) clozapine (clozaril) Citalopram (Celexa) amphetamine (Dexedrine) olanzapine (zyprexa) Fluoxatine (Prozac) dextroamphetamine quetiapine (Seroquel) Paroxetine (Paxil) (Adderall) risperidone (Risperdal Sertraline (Zoloft) dexmethylphenidate (Focalin) methylphenidate (Ritalin)
Spatio-temporal Cluster Detection • Spatial Scan Statistic • Two sets for each study medication • Cases only (space-time permutation model) • Cases versus controls (Bernoulli model) • Focused on first 90 days after medication available • Retrospective space-time analysis • Time aggregation – month • Space - 5 digit ZIP • Clusters: circular, less than 50% period or geography
Hierarchical Models • Hierarchical cross-classified generalized linear model • Select unique children (first prescription, initiation) • Model child getting study versus control medication • Observations cross-classified by ZIP and month • Level one: children • Level two: ZIP and month (space & time) • L1 covariates: age, sex, race • L2 covariates: ZIP type, number of detailing visits • NB: omitted Straterra Time period for HCCGLMs ends December 31, 2003
Psychiatrist Access • Ratio of Psychiatrist to PCP MDs within clusters versus rest of Michigan • Psychiatrists per capita within clusters versus rest of Michigan
Results
Child count during first year 7000 6000 5000 Number of Children Abilify 4000 Concerta Geodon 3000 Lexapro 2000 1000 0 1 2 3 4 5 6 7 8 9 10 11 12 Months on Michigan Medicaid Formulary
New Rx in the first year 3500 3000 2500 Number of Children Geodon 2000 Lexapro Abilify 1500 Concerta 1000 500 0 1 2 3 4 5 6 7 8 9 10 11 12 Months on Michigan Medicaid Formulary
Commercial Detailing Effort Abilify: National Monthly Expenditure on Meetings, and Detailing During the First 12 Months on the Market 10 Monthly Expenditure (millions) 8 6 4 FDA approval 11/15/2002 2 Note: the observation for October 2002 is the sum of expenditures between June 2002 and October 2002 0 Oct-02 Nov-02 Dec-02 Jan-03 Feb-03 Mar-03 Apr-03 May-03 Jun-03 Jul-03 Aug-03 Sep-03 Oct-03 Month of Availability
Concerta: National Monthly Expenditure on Meetings, and Detailing During the First 12 Months on the Market 10 Monthly Expenditure (millions) 8 6 4 2 Note: pre-market expenditures on Concerta were zero. 0 Jul-00 Aug-00 Sep-00 Oct-00 Nov-00 Dec-00 Jan-01 Feb-01 Mar-01 Apr-01 May-01 Jun-01 Jul-01 Month of Availability
Geodon: National Monthly Expenditure on Meetings, and Detailing During the First 12 Months on the Market 10 Monthly Expenditures Millions 8 6 4 2 FDA approval 2/5/2001 Note: the observation for Jan 2001 is the sum of expenditures between June 1999 and Jan 2001 0 Jan-01 Feb-01 Mar-01 Apr-01 May-01 Jun-01 Jul-01 Aug-01 Sep-01 Oct-01 Nov-01 Dec-01 Jan-02 Month of Availability
Lexapro: National Monthly Expenditure on Meetings, and Detailing During the First 12 Months on the Market 30 Monthly Expenditures (Millions) 25 20 15 10 FDA approval 8/15/2002 5 Note: the observation for July 2002 is the sum of expenditures between April 2001 and July 2002 0 Jul-02 Aug-02 Sep-02 Oct-02 Nov-02 Dec-02 Jan-03 Feb-03 Mar-03 Apr-03 May-03 Jun-03 Jul-03 Month of Availability
Primary Clusters – Space-Time Permutation Cadillac Big Rapids Flint Grand Rapids ABILIFY LEXAPRO Lansing Detroit Kalamazoo Ann Arbor STRATERRA GEODON 0 25 50 CONCERTA miles
Primary Clusters Identified Cases only: space-time permutation model Exp’d Drug r Base Obs. RR LLR P-value Begin end miles Pop Cases Cases Abilify 20.9 1756 9 .44 27.98 19.9 0.001 1/14/03 2/13/03 Concerta 125.8 9290 686 240.2 4.3 370.4 0.001 10/01/00 10/30/00 Geodon 20.5 2382 26 2.2 17.3 44.5 0.001 4/7/01 5/6/01 Lexapro 24.2 1354 4 0.19 27.1 8.84 0.066 10/14/02 11/13/02 Straterra 110.2 1896 56 2.5 33.7 131.9 0.001 1/25/03 2/24/03
Primary Clusters - Bernoulli • Strattera • Abilify • Geodon • Lexapro • Concerta county cluster centers atomoxetine aripiprazole ziprasidone escitalopram methylphenidate extended release 0 50 100 miles
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