This study will involve the evaluation of the cost profile of about approximately 241,000 patients (15,000 who are members of the Generations Plus/ Northern Manhattan Health Network AND 226,000 members of a large self insured union trust fund). We will test the hypothesis that as comorbidity scores exceed three-four, patients will have an exponential increase in average yearly cost with a parallel exponential increase in cost variability.

We will examine the relationship between comorbidity and health insurance costs and variability in costs among patients enrolled in health plans.

Inclusion Criteria:

• patients with different burdens of comorbidity who have at least two continuous years of enrollment in the Generations Plus/ Northern Manhattan Health Network between June 2007 to July 2009 and members of a large self insured union trust fund from 2007-2010

Approximately 15,000 patients who were continuously enrolled during the calendar years 2006 and 2010 in the Generations Plus/ Northern Manhattan Health Network and 226,000 members of a large self insured union trust fund from 2007-2010 will be combined. The data will include age, gender, length of plan enrollment, whether or not the patient is disabled, their diagnoses, and their use of medical and social services.