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

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

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Estimating costs of diagnosis and treatment for lung cancer using linked longitudinal data A seminar presented at the British Columbia Cancer Agency, Vancouver, Canada – PowerPoint PPT presentation

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


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

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

3
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
    methodcensoring 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 time s
7
  • Need a set of unbiased estimators of the set of
    hazards rs
  • 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.
  • n150

11
(No Transcript)
12
Lung cancer cases
13
Age at diagnosis - BSC
14
Survival
15
Survival by stage
16
Treatment summary numbers of items
17
Average cost per patient-month from date of last
chemotherapy(CAD, current prices, undiscounted)
18
Average cost per patient-month by month of
follow-up
19
Average cost per patient-month over various
periods of follow-up(CAD, current prices,
undiscounted)
20
Average cost per patient-month from date of last
chemo vs BSC date(CAD, current prices,
undiscounted)
21
Lifetime treatment costs (LTC) were estimated by
applying Kaplan-Meier monthly survival
probabilities to average cost per month. The
formula with monthly discounting is
22
Lifetime treatment costs(CAD)
23
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
24
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.

25
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.

26
Demographic Diagnostic Characteristics
Gender n 543
Female Male 40.5 (220) 59.5 (323)
Age at Diagnosis n 541
lt40 40-60 61-80 gt80 Median 1.3 (7) 21.1 (114) 65.6 (355) 12.0 (65) 68.6 yrs
27
Demographic Diagnostic Characteristics
Stage at Diagnosis n 530
I II III IV 10.0 (53) 6.5 (35) 35.0 (185) 48.5 (257)
Method of Diagnosis n 541
FNA Bronchoscopy Mediastinoscopy Thoracotomy Other 30.5 (165) 38.8 (210) 5.9 (32) 7.9 (43) 16.9 (91)
28
Waiting time intervals
Waiting Times n median 25th to 75th ile
Symptom to 1st CXR 1st CXR to 1st CT 1st CT to Diagnosis 328 346 346 26 days 10 days 18 days 7 to 62 days 1 to 31 days 6 to 36 days
Symptom to Diagnosis 469 72 days 41 to 124 days
29
Factors affecting waiting time
30
Cost Analysis for Diagnosis of NSCLC
Test or Service Subtotal Cost Mean Cost per Pt (n 464)
Total (excluding inpatient costs) 191,784 413.30
Total (including inpatient costs) 3,019,435 6,507.40
31
Costs of diagnosis by type of service
Test or Service Mean Cost per Patient (n 464)
Diagnostic 263.10
Staging 26.00
Physician Visits 121.10
Inpatient 6,094.10
Others 3.10
TOTAL 6,507.40
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