Appendix Table 1.

Panel A. Definitions for Depression and Heart Failure
Chronic Conditions	Reference Time Period	Valid ICD-9 Codes	Number/Type of Claims to Qualify
Depression	1/1/2007–12/31/2007	DX: 296.2–296.6, 296.89, 298.0, 300.4, 309.1, and 311 (any DX on the claim)	At least 1 claim with DX codes during the 1-yr period (2007)
Heart Failure	1/1/2006–12/31/2007	DX: 398.91, 402.01, 402.11, 402.91, 404.01, 404.11, 404.91, 404.03, 404.13, 404.93, 428.0X-428.4X, 428.9X (any DX on the claim)	At least 1 inpatient, outpatient or physician claim with DX codes during the 2-yr period (2006–2007)

Panel B. Drug Classes Used to Treat Depression and Heart Failure
Chronic Medical Illnesses	Major Drug Classes
Depression	Selective Serotonin Reuptake Inhibitors (SSRIs), Serotonin/Noradrenaline Reuptake Inhibitors (SNRIs), tricyclic antidepressants, Alpha-2 Receptor Antagonists (NaSSA), MAO Inhibitor Nonselective & irreversible, Norepinephrine & Dopamine Reuptake Inhibitors (NDRIs), Serotonin-2 Antagonist-Reuptake Inhibitors (SARIs) and the combination drugs
Heart failure	Angiotensin-Converting Enzyme inhibitors (ACEi), Angiotensin II Receptor Blockers (ARB), beta blockers, Calcium Channel Blockers, diuretics, vasodilators, digoxin