HEALTHCARE UTILIZATION IN QUEBEC IMMIGRANTS AND NON-IMMIGRANTS

WITH CHRONIC HEPATITIS C INFECTION

Rhiannon KamstraM.Sc. Student

McGill EBOH 50th AnniversaryMay 1st, 2015

Supervisor:Dr. Christina GreenawayThesis committee:Dr. Laurent AzoulayDr. Marina KleinDr. Russell Steele

Chronic Hepatitis C

30% develop liver disease in 20-30 years

HCC

Cirrhosis

Liver failur

e Transplant

Up to 85% of people infected byHepatitis C Virus become chronically infected

2WHO Guidelines (April 2014)

Transmission

BLOOD PRODUCTSPre-screening era

INJECTION DRUG USE

MEDICAL PROCEDURES

60% of new cases in Canada

300k cases/year from unsafe injections

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Burden

350k global deaths per year

185 millioninfections worldwide

250,000 Canadians infected

At least 35% of cases are undetected

4Mohd Hanafiah et al. Hepatology (2013)Lavanchy D. Liver Int. (2009)Hepatitis C In Canada: 2005-2010 Surveillance Report (PHAC)

Rising healthcare use

Myers et al. Can J Gastroenterol Hepatol (2014)Hepatitis C In Canada: 10 2005-2010 Surveillance Report (PHAC)

Projected 60% increase in annual costs due to HCV in Canada over the next 20 years(Myers

2014)

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Immigrants

Hepatitis C In Canada: 2005-2010 Surveillance Report (PHAC)Evolving epidemiology of hepatitis C virus. Lavanchy (2011)

Very limited data – modelling estimates suggest 20% of cases in Canada occur in immigrants

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Often migrate from regions with

high prevalence

Different risk factors and health status

WHY? Inform policy and planning with data about healthcare utilization in the Quebec HCV-infected population

Immigrants are a unique subgroup – understanding differences will help prevention and treatment efforts

Rationale

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ObjectiveEstimate and compare all-cause andliver-related healthcare utilization for immigrants and non-immigrants with HCV, identifying predictors of utilization

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9

Study DesignRetrospective longitudinal cohort study

Cases ascertained from mandatory reportable disease database (MADO) from 1998-2007

Date of diagnosis

Censoring

Death

Loss of RAMQ

coverage (>6 months) End of

studyDec. 31, 2007

1 year prior to diagnosis

Assess prevalent comorbidities

Measure incident healthcare utilization

• AGE• SEX• LOCATION• COVERAGE

• ARRIVAL DATE• COUNTRY OF ORIGIN

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Deterministic linkageRAMQ ID

MED-ECHOHOSPITALIZATIONSDIAGNOSTIC CODES

PROCEDURES

HEALTH SERVICES

DATA

PHYSICIAN BILLING

OUTPATIENT VISITSBILLING CODES

Deterministic linkageVISA #

Cohort Selection

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Definitions

Focused on hospitalizations as measure of healthcare utilization• Liver-related complications are serious

Primary measures of healthcare utilizationHospital stays (N)Days in hospital (N)

Liver-related hospitalizations required at least one diagnostic code (ICD 9, ICD 10, or procedure code) to match a specified list (including cirrhosis, liver transplant, liver cancer)

Prevalent comorbidities were identified using hospitalizations and physician billing using ICD 9 and 10 codes

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Analysis

Summarize and compare characteristics of hospitalizations in immigrants and non-immigrants (e.g., mean N per subject, rate per 100PY, length of stay, reason for stay)

Examined influence of demographic differences on rate of hospitalizations in immigrants/non-immigrants using negative binomial modelling

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2

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Demographics

Immigrantsaccounted for

9% of cases

Time from arrival to diagnosis was 9.8 ± 6.9 years

N = 20,139 cases (1998-2007)Median follow-up: 3.9 years (immigrants)

4.8 years (non-immigrants)

26% originated from

East Asia/Pacific(most common region of origin)

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DemographicsImmigrants

Older at diagnosis (47.6 years vs. 43.2 years)Only 53% male (vs. 68%)78% located in Montreal (vs. 38%)

Cirrhosis Decompensated HCC Diabetes Alcohol abuse Drug abuse HIV0

5

10

15

20

25ImmigrantsNon-immigrants

Pre

va

len

ce (

%)

Drug/alcohol related4-10x more common in non-immigrants

More frequent in immigrants at

baseline

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All-cause hospitalizations

Most subjects were never hospitalized during follow-up.

Non-immigrants had a higher burden of all-cause hospitalizations

CharacteristicImmigrantsN = 1821

Non-immigrantsN = 18318

p

N (%) ever hospitalized 652 (35.80) 9032 (49.31)<.0001

Total hospitalizations (N) 1525 29239

Mean stays per person (95% CI) 0.84 (0.76-0.92) 1.60 (1.56-1.64)<.0001

Crude rate of stays / 100 PY 22.1 (20.2-24.2) 37.1 (36.2-38.1)  

Mean days per person (95% CI) 7.34 (6.31-8.37)15.77 (15.01-16.53)

<.0001

Crude rate of hospital days / 100 PY

167.3 325.7

Mean length of stay ± SD (days) 11.37 ± 16.61 11.51 ± 25.25

49.3% of non-immigrants

ever hospitalized

Stays per subject and per person-time higher in non-immigrants

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All-cause hospitalizations

Non-immigrants

Category of primary diagnosis% of all hospitalizations

Immigrants

1 Liver/viral hepatitis11.6%

2 Nervous system/sense organs10.2%

3 Pregnancy/childbirth8.7%

Mental disorders20.5%

Injury & poisoning10.3%

Digestive system (excl. liver)8.7%

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Liver-related hospitalizations

7.2% of subjects contributed all liver-related stays

Liver-related hospitalization was similar for immigrants and non-immigrants despite comorbidities

Most in-hospital deaths in immigrants were liver-related (57.9% vs. 41.8%)

CharacteristicImmigrantsN = 1821

Non-immigrantsN = 18318

p

N (%) ever hospitalized 142 (7.80) 1299 (7.09) 0.27

Total hospitalizations (N) 286 3164

Mean stays per person (95% CI) 0.16 (0.13-0.19) 0.17 (0.16-0.18) 0.63

Crude rate of stays / 100 PY 6.4 (4.7-8.6) 5.8 (5.3-6.4)  

Mean days per person (95% CI) 2.32 (1.72-2.92) 2.37 (2.16-2.58) 0.89

Rate of hospital days / 100 PY 52.9 48.8

Mean length of stay ± SD (days) 15.17 ± 21.02 14.04 ± 21.11

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Modelling

What is driving similar rates of liver-related hospitalization vs. different all-cause

CovariateUnivariateRate ratio, 95%CI

pMultivariate(Rate ratio, 95%CI

p

Immigrant status

Non-immigrant REFERENCE REFERENCE

Immigrant 0.60 (0.54-0.65) <.0001 0.52 (0.47-0.57) <.0001

Age (cont.) 1.02 (1.02-1.02) <.0001 1.02 (1.02-1.02) <.0001

Sex

M REFERENCE REFERENCE

F 1.26 (1.16-1.29) <.0001 1.28 (1.21-1.34) <.0001

All-cause hospitalizations

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Modelling

What is driving similar rates of liver-related hospitalization vs. different all-cause

CovariateUnivariateRate ratio, 95%CI

pMultivariate(Rate ratio, 95%CI

p

Immigrant status

Non-immigrant REFERENCE REFERENCE

Immigrant 1.10 (0.80-1.49) <.5652 0.69 (0.52-0.92) 0.0102

Age (cont.) 1.09 (1.08-1.09) <.0001 1.09 (1.08-1.09) <.0001

Sex

M REFERENCE REFERENCE

F 0.89 (0.74-1.06) 0.1935 0.69 (0.59-0.82) <.0001

Relative rate of liver-related affected by different age and sex distribution

Liver-related hospitalizations

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Discussion

• Immigrants are different – implications for prevention and treatment

• Non-immigrants have more all-cause hospitalization but similar liver-related– Despite more prevalent risk factors for progression

(alcohol, HIV)

• Suggests other drivers of liver-related in immigrants– Older age (late detection)

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Main limitations• Passive detection and reporting– Symptom-based screening– Determined by care-seeking

• Non-linkage – 20% non-linkage to RAMQ

• Limited accuracy of diagnostic coding– Defining liver-related stays, comorbidities– Detection depends on care seeking

• Reference group

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Acknowledgements

Supervisor: Dr. Chris Greenaway

Thesis committee members:Dr. Laurent AzoulayDr. Marina KleinDr. Russ Steele

Members of the Greenaway team:Alain, Viet, Nour & Catherine

McGill and LDI staff

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References &

ResourcesLavanchy, D. "The global burden of hepatitis C." Liver International 29.s1 (2009): 74-81.

Lavanchy, D. "Evolving epidemiology of hepatitis C virus." Clinical Microbiology and Infection 17.2 (2011): 107-115.

Lozano R, Naghavi M, Foreman K, Lim S, Shibuya K, Aboyans V, et al. Global and regional mortality from 235 causes of death for 20 age groups in 1990 and 2010: a systematic analysis for the Global Burden of Disease Study 2010. The Lancet. 2012; 380(9859): 2095-128.

Mohd Hanafiah K, Groeger J, Flaxman AD, Wiersma ST. Global epidemiology of hepatitis C virus infection: New estimates of age-specific antibody to HCV seroprevalence. Hepatology. 2013; 57(4): 1333-42.

Myers, Robert P., et al. "Burden of disease and cost of chronic hepatitis C virus infection in Canada." Canadian journal of gastroenterology & hepatology28.5 (2014): 243.

Public Health Agency of Canada. Hepatitis C in Canada: 2005-2010 Surveillance Report; 2012. (Online)

Remis RS. Modelling the incidence and prevalence of hepatitis C infection and its sequelae in Canada, 2007. Health Canada, Ottawa: Final report. 2007.

World Health Organization (WHO). Guidelines for the screening, care and treatment of persons with hepatitis C infection. April 2014. (Online)

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Questions