University of Texas Health Science Center EXPLAINING HEALTH CARE UTILIZATION FOR PANIC ATTACKS USING CUSP CATASTROPHE MODELING David Katerndahl, M.D.,M.A. University of Texas Health Science Center San Antonio, Texas

PROBLEM Panic Disorder Patients High Utilizers Often Multiple Sites For Panic Symptoms Correlates Of Utilization Predisposition To Utilization Symptom Perceptions Family Utilization Prior Experience With Health Care Stressors General Stress Symptom Severity Phobic Avoidance Problems High Unmet Needs Inconsistent Findings Variance Accounted Is Low Is Utilization A Nonlinear Phenomenon?

CUSP CATASTROPHE MODELING Characteristics Bimodal Distributions Of Outcome Depending On Stressor Behavior Jumps At Different Levels Of Predisposition At High Stress, Certain Outcome Values Not Observed Features Of Predisposition-Outcome Relationship Low Stress Environment – Linear Relationship High Stress Environment – Sudden Jumps Prior Applications Adolescent Smoking And Drinking Decision-Making Perceptions Attitudinal Change Eating Behavior

CUSP CATASTROPHE MODELING

PURPOSE To Compare The Fit Of Linear And Cusp Catastrophe Models To Explain Changes In Health Care Utilization For Panic Symptoms

METHODS Sample – Secondary Analysis (PACT Study) Instruments Community-Based Randomly-Selected Households Randomly-Selected Adults DSM-IIIR Criteria For Panic Attacks (SCID) Instruments Stressor Variable – Severity Of Panic Phobic Anxiety Scale - Symptom Checklist-90 (SCL-90) Predisposing Variables Total Family HC Use - Family Health Care Utilization Questionnaire Symptom Perception Scales Need For Treatment Life Threat Treatment Experience Scale - Illness Attitude Scales Outcomes - Health Care Utilization Questionnaire 2-Month Utilization When First Seeking Care & Last 2 Months Health Care Sites & Self-Treatments Used For Panic Symptoms

ANALYSIS Outcomes = Number Of Sites/TXs Used For Panic Symptoms Emergency Sites/Providers General Health Sites/Providers Mental Health Sites/Providers Total Health Care Sites/Providers Self-Treatments Analysis Bimodality At High Stress Comparison Of Models – Using Z-Transformations Linear Models Cusp Catastrophe Model Criteria For Cusp Catastrophe Acceptance Bimodality Adjusted R2 Superior To Linear Models All Terms In Cusp Model Significant (p≤0.1)

DEMOGRAPHICS OF THE SAMPLE (n=97)

BIMODALITY ASSESSMENT Method Emergency Sites/Providers General Health Sites/Providers Mental Health Sites/Providers Total HC Sites/Providers Self Treatments Graphic Bimodal Yes Unclear No Standard Deviation SCL 0-1 SCL 1-2 SCL 2-3 SCL 3-4 0.28 0.49 0.30 0.38 0.71 0.56 0.42 0.51 0.59 0.69 1.15 0.67 1.11 0.61 0.77 0.94 1.07

MODELS OF EMERGENCY SITES/PROVIDERS [beta(p)] PredispositionModels Perceived Life Threat Perceived Need For Treatment Family HC Use Treatment Experience Linear Δt2-t1 Predispose SCL Adjusted R2 Interaction* t2 Use t1 Use .07 .01 -.00 .18# -.02 .49**** .281**** -.06 .05 .04 .06 .02 .51**** .255**** -.01 .03 -.03 .52**** .253**** -.04 .09 .50**** .260**** Cusp t1 Use3 t1 Use2 Interaction** .89** -1.33**** .19* .18* .244**** .86* -1.28**** .83 .216**** .82* -1.23**** .17# .210**** .83* -1.25**** .214**** # p≤0.1, * p≤.05, ** p≤.01, *** p≤.005, **** p≤.001 # p≤0.1, * p≤.05, ** p≤.01, *** p≤.005, **** p≤.001 Interaction* = Predispose X SCL, Interaction** = t1 Use X SCL

MODELS OF MENTAL HEALTH SITES/PROVIDERS [beta(p)] PredispositionModels Perceived Need For Treatment Family HC Use Treatment Experience Linear Δt2-t1 Predispose SCL Adjusted R2 Interaction* t2 Use t1 Use .09 -.11 .83 -.96 -.71 .10 -.01 .37**** .122*** -.25* -.10 .050* -.24* -.08 .046# -.15 .01 .40**** .161**** .11 .13 -.09 -.12 .003 .43**** .21* .268**** Cusp t1 Use3 t1 Use2 Interaction** .52 -1.29** .36**** .05 .363**** .28 -.10* .35**** .374**** 1.04* -1.91**** .470**** # p≤0.1, * p≤.05, ** p≤.01, *** p≤.005, **** p≤.001 Interaction* = Predispose X SCL, Interaction** = t1 Use X SCL

MODELS OF SELF TREATMENTS [beta(p)] Predisposition Models Perceived Need For Treatment Treatment Experience Linear Δt2-t1 Predispose SCL Adjusted R2 Interaction* t2 Use t1 Use .12 .07 .004 .09 -.13 .009 .11 .34**** .121*** -.01 -.04 .23* .27** .156**** Cusp t1 Use3 t1 Use2 Interaction** 1.57*** -.09**** .15 .356**** 1.59**** -2.19**** .16# .21* .383**** # p≤0.1, * p≤.05, ** p≤.01, *** p≤.005, **** p≤.001 Interaction* = Predispose X SCL, Interaction** = t1 Use X SCL

DISCUSSION Cusp Catastrophe Models Superior Mental Health Sites/Providers Use Use of Self Treatments Emergency Sites/Providers Use May Be Cusp Catastrophe Phenomenon Model May Be Incomplete Implications For High Stress Situations Panic Patients Will Maintain Their Behavior Change Only Comes When: They Realize Panic Will Not Resolve Itself They Realize That It Is No Longer Reasonable Not To Change Prior Treatment Experience With HC System Critical Reducing Phobic Avoidance May Increase Predictability Of Use

LIMITATIONS Care-Seeking Behavior Sample Predominantly Based On Recall Number Of Sites, Not Number Of Visits Sample Predominantly Hispanic Low SES Multiple Comparisons Used

CONCLUSION Cusp Catastrophe Modeling May Better Reflect Health Care Utilization Than Linear Models Implications For Dealing With Patients With Panic Attacks Prior Treatment Experience Important Treating Phobic Avoidance May Improve Predictability Educate Patients Panic Attacks Rarely Resolve On Their Own Unreasonable To Maintain Inappropriate Behavior