Cohort Definition Name : Earliest event of Chronic Leukocytic Leukemia
Contributor name : Jill Hardin’
Contributor OrcId :
Logic Description : Earliest event of Chronic Leukocytic Leukemia (not including Hairy cell, prolymphocytic leukemia, T cell, reticuloendotheliosis) for the first time in persons history, exit cohort at the end of continuous observation period.
Recommended study application : target
Assertion statement : This cohort definition was executed on at least one real person-level observational health data source and resulted in a cohort with at least 1 person.
Target Clinical Description : Chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL) are cancers that affect lymphocytes. CLL and SLL are essentially the same diseases, the only difference is the location where the cancer primarily occurs. In CLL, most of the cancerous lymphocytes are located in the bloodstream and the bone marrow, although the lymph nodes and spleen are often involved. In SLL, the cancer cells are located mostly in the lymph nodes
"Evaluation conclusion : We developed a prevalent cohort definition for chronic lymphocytic leukemia (CLL SLL) which incorporated all those codes found from the literature review and from the analysis of PHOEBE and orphan concepts in cohort diagnostics. (NOTE: there are several excluded concepts oer guidance of clinical expert opinion). We performed the evaluation across a network of claim data sources and 1 EHR US data source. The data sources are: IBM® MarketScan® Commercial Database (CCAE), Optum’s longitudinal EHR repository (Optum EHR), Optum’s Clinformatics® Data Mart (DOD), IBM® MarketScan® Multi-State Medicaid Database (MDCD), IBM® MarketScan® Medicare Supplemental Database (MDCR), Japan Claims Database (JMDC), Clinical Practice Research Datalink (CPRD) , IQVIA® Australia Longitudinal Patient Data (LPD) database (Australia), IQVIA® Disease Analyzer (DA) France database (France), QVIA® Disease Analyzer (DA) Germany database (Germany), IQVIA® Adjudicated Health Plan Claims Data (formerly PharMetrics Plus) - US database (PharMetrics), IQVIA® Ambulatory EMR (EMR). The algorithm retrieves subjects from all 11 databases tested. We developed a more specific cohort requiring a second diagnosis code for CLL SLL in the time period 31-365 days after index. This cohort improves the sensitivity of the algorithm albeit at the expense of PPV as determined by PheValuator. Because use of second codes is not common in some databases, the use of codes in future can result in immortal time bias, and the use of an algorithm using 2 codes in this case does not dramatically alter the sensitivity and positive predictive value metrics, we recommend using the algorithm requiring only 1 code.
Performance characteristics were determined for 6 of the 11 databases. The remaining databases did not contain enough subjects to produce an accurate diagnostic model. Using this definition (one code), sensitivity ranged from about 84% in EHR to about 97% in DOD while positive predictive value ranged from about 72% in MDCD to about 82% in DOD. Using another definition (using 2 codes), sensitivity decreased, ranging from about 64% in EHR to about 88% in DOD while positive predictive value increased, ranging from 92% in MDCD to about 96% in CCAE.
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