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Estimating costs of diagnosis and treatment for lung cancer using linked longitudinal data

Estimating costs of diagnosis and treatment for lung cancer using linked longitudinal data. Jim Butler Australian National University. A seminar presented at the British Columbia Cancer Agency, Vancouver, Canada 1 December 2006. Overview. Some issues in methods Study 1 – Treatment costs

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Estimating costs of diagnosis and treatment for lung cancer using linked longitudinal data

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  1. Estimating costs of diagnosis and treatment for lung cancer using linked longitudinal data Jim Butler Australian National University A seminar presented at the British Columbia Cancer Agency, Vancouver, Canada 1 December 2006

  2. Overview • Some issues in methods • Study 1 – Treatment costs • Study 2 – Diagnosis costs (in progress)

  3. T0 T1 T2 T3 T4 T0 Disease onset T1 Symptoms appear T2 First contact with health care system T3 Definitive diagnosis – commence treatment T4 End of episode (cure/death) Some issues in method Time period of observation

  4. Censoring • Costs accumulate over time to a defined event (e.g. death) • Censored observations arise from subjects who are not followed to the defined event:- still alive at end of study- lost to follow-up during study • Apply survival analysis to cost data • Bias may arise if underlying assumptions are not satisfied

  5. Key assumption in applying Kaplan/Meier method:censoring is independent of time-to-event (independent censoring) • → non-censored subjects are representative of all subjects • → censored subjects are neither a relatively high-risk sub-population nor a relatively low-risk sub-population

  6. Probability that time to event T exceeds any given value t is given by {s1, s2, …} = observed failure times rs = risk of failure at times

  7. Need a set of unbiased estimators of the set of hazardsrs • Even if independent censoring characterises time-to-event analysis, it may not characterise cost-to-event analysis e.g. low-cost subjects may be more likely to drop out • Extent of problem is an empirical matter • Less likely to be a problem with analyses using population-based data (e.g. people leaving region/province/country are the source of drop-out)

  8. Study 1 SURVIVAL AND TREATMENT COSTS OF A POPULATION-BASED SAMPLE OF STAGE IIIb/IV NON-SMALL CELL LUNG CANCER (NSCLC) PATIENTS ONBEST SUPPORTIVE CARE (BSC) Erich KliewerJim ButlerAlain Demers Sri Navaratnam Grace Musto Coreen Hildebrand

  9. Objectives • For stage IIIb/IV NSCLC patients in BSC phase of treatment describe their: • chemotherapy treatment prior to BSC • survival since start of BSC • treatment since start of BSC • costs of treatment since start of BSC

  10. Study Population • Patients diagnosed with stage IIIb/IV NSCLC in Manitoba between March 1997-June 2000 and who had survived at least 28 days since last chemotherapy (BSC phase). • If stage IIIb they had to have either pleural effusion or supraclavicular lymph node metastsis. • n=150

  11. Lung cancer cases

  12. Age at diagnosis - BSC

  13. Survival

  14. Survival by stage

  15. Treatment summary – numbers of items

  16. Average cost per patient-month from date of last chemotherapy(CAD, current prices, undiscounted)

  17. Average cost per patient-month by month of follow-up

  18. Average cost per patient-month over various periods of follow-up(CAD, current prices, undiscounted)

  19. Average cost per patient-month from date of last chemo vs BSC date(CAD, current prices, undiscounted)

  20. Lifetime treatment costs (LTC) were estimated by applying Kaplan-Meier monthly survival probabilities to average cost per month. The formula with monthly discounting is:

  21. Lifetime treatment costs(CAD)

  22. Study 2 ANALYSIS OF WAITING TIMES AND COSTS FOR THE DIAGNOSIS OF NON-SMALL CELL LUNG CANCER Winson Cheung Steve Welch Jim ButlerErich Kliewer Alain Demers Grace Musto Sri Navaratnam

  23. Objectives • To assess the timeliness of the diagnosis of non-small cell lung cancer (NSCLC) in Manitoba and to evaluate the variables that affect these waiting times. • To quantify the costs involved in the diagnosis of NSCLC in Manitoba. • To correlate data collected by chart review with information from the Manitoba Health administrative databases.

  24. Methods • Patients diagnosed with NSCLC from January 1, 1996 to December 31, 2000 were identified using the Manitoba Cancer Registry. • Information on demographics, diagnostic and staging tests, timeline of investigations, and outcomes were collected by systematic, retrospective chart review for 543 patients. • Similar information was obtained from the Manitoba Health administrative databases for 472 of the patients.

  25. Demographic & Diagnostic Characteristics

  26. Demographic & Diagnostic Characteristics

  27. Waiting time intervals

  28. Factors affecting waiting time

  29. Cost Analysis for Diagnosis of NSCLC

  30. Costs of diagnosis by type of service

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