Evaluation of the New Jersey Silicosis Surveillance System, 1993-2008

Jessie Gleason, MSPH

CDC/CSTE Applied Epidemiology FellowNew Jersey Department of Health and Senior Services

Environmental and Occupational Health Surveillance Programjessie.gleason@doh.nj.state.us

June 6, 2012

Disease BackgroundSilicosis

• Occupational lung disease• Respirable crystalline silica• Fatal – Irreversible• Preventable• Long latency period

Surveillance SystemBackground

• Silicosis surveillance: New Jersey and Michigan

• NIOSH has funded New Jersey since 1987• Silicosis surveillance is part of the Sentinel

Events Notifications Systems for Occupational Risk (SENSOR)

Silicosis Surveillance System

Two steps:

1.Report Sources: A. Hospital Discharge Data B. Death CertificatesC. Emergency Department DataD. Worker’s CompensationE. Physician Reports

Silicosis Surveillance System

2. Case Confirmation Requirements:A. History of occupational exposure to

airborne silica dustAnd Either or Both of the Following:B1. Chest radiograph or other imaging

techniqueB2. Pathologic findings

Evaluation of the Silicosis System

• 2001 Updated Guidelines for Evaluating Public Health Surveillance Systems, CDC

• Attributes: Positive Predictive Value (PPV), Representativeness, Data Quality, Simplicity, Timeliness, Flexibility, Stability

• Methods: Staff interviews, Review of

system documentation, database, publications and relevant literature

Positive Predictive Value (PPV)

• Proportion of reported potential cases which actually have the event

• Number of Confirmed Cases/Total Number of Potential Cases Reported

• PPV was calculated:– Overall – Report source by each status outcome

Positive Predictive Value by Primary Reporting Source, 1993-2008

Report Source

Reported N

Confirmed

N (PPV%)

NoN (%)

Insufficient

N (%)

MissingN(%)

Hospital 466 180 (39%)

93 (20%)

113 (24%) 42 (9%)

Death Certificate

29 5 (17%) 3 (10%) 15 (52%) 1 (3%)

Emergency Department

14 2 (14%) 3 (21%) 5 (36%) 3 (21%)

Worker’s Compensation

7 0 (0%) 0 (0%) 0 (0%) 7 (100%)

Physician Reports

6 2 (33%) 1 (17%) 2 (33%) 1 (17%)

Total 528 192 (36%)

102 (19%)

135 (26%) 55 (10%)

Positive Predictive Value - Key Findings

• Overall PPV is low (36%)• Hospital Discharge Data has the highest

PPV (39%)• Insufficient:– 52% of Death Certificates– 36% Emergency Department Data– 24% Hospital Discharge Data

• Missing: 100% Worker’s Compensation

Representativeness

• “A representative system accurately describes the occurrence of health-related events over time and its distribution in the population by place and person” 1

• Compared confirmed silicosis cases to potentially silica-exposed New Jersey workforce2

• Chi-square goodness of fit

1. (2001) Updated Guidelines for Evaluating Public Health Surveillance Systems, Centers for Disease Control and Prevention. Morbidity and Mortality Weekly

2. Estimates of workforce by gender, race, ethnicity and industry obtained from the Bureau of Labor and Statistics, New Jersey, 2010

Comparison of Demographic and Workforce Characteristics for Confirmed Silicosis Cases, (1993-2008) and Bureau of Labor

Statistics, New Jersey Workforce, (2010)

Characteristics

Labor Estimates

Silicosis Registry – Confirmed

Case

P-value

Gender 0.9801

Male 630000 (84%)

165 (86%)

Female 116000 (16%)

27 (14%)

Total 746000 192

Race 0.0511

White 610000 (82%)

161 (88%)

Black 93000 (12%) 18 (10%)

Other 42000 (6%) 4 (2%)

Total 745000 183

Ethnicity <.0001

Hispanic 259000 (35%)

11 (7%)

Non-Hispanic

487000 (65%)

166 (94%)

Total 746000 177

Comparison of Demographic and Workforce Characteristics for Confirmed Silicosis Cases, (1993-2008) and Bureau of Labor

Statistics, New Jersey Workforce, (2010) - continued

Characteristics

Labor Estimates

Silicosis Registry

– Confirme

d Case

P-value

Occupation <.0001

Farming 10000 (1%) 1 (1%)

Construction

158000 (21%)

51 (28%)

Installation 121000 (16%)

9 (5%)

Production 154000 (21%)

108 (60%)

Transportation

254000 (34%)

10 (6%)

Architecture 49000 (7%) 5 (3%)

Total 746000 179

Representativeness – Key Findings

• Gender (p-value >.05)– 86% Male silicosis cases vs. 84% Male

workforce• Race (p-value >.05)• Occupation (p-value <.05)• Ethnicity – 7% Hispanic silicosis cases vs. 35%

Hispanic workforce (p-value <.05)

Report Source, Gender, and Occupation by Ethnicity for Confirmed Silicosis Cases, (1993-2008)

Characteristics Hispanic Non- Hispanic

Unknown

Ethnicity

P-value

Report Source <.001*

Hospital and Emergency

7 (63%) 162 (98%)

13 (87%)

Physician reports 1 (9%) 1 (1%) 0 (0%)

Death Certificates 2 (18%) 3 (2%) 0 (0%)

Worker’s Compensation

0 (0%) 0 (0%) 0 (0%)

Other 1 (9%) 0 (0%) 2 (13%)

Gender 0.380

Male 11 (100%)

142 (86%)

12 (80%)

Female 0 (0%) 24 (14%)

3 (20%)

Occupation 0.114

Construction 3 (27%) 44 (27%)

4 (29%)

Installation 1 (9%) 7 (4%) 1 (7%)

Production 4 (36%) 98 (61%)

6 (43%)

Other 3 (27%) 13 (8%) 3 (21%)

*Fisher’s Exact Test evaluated at a 0.05 significance level

Report Source and Gender by Ethnicity for Reported Potential Silicosis Cases, (1993-2008)

Characteristics Hispanic Non- Hispanic

Unknown

Ethnicity

P-value

Report Source <.004*

Hospital and Emergency

18 (75%) 378 (92%)

84 (89%)

Physician reports 1 (4%) 4 (1%) 1 (1%)

Death Certificates 3 (13%) 21 (5%) 5 (5%)

Worker’s Compensation

1 (4%) 6 (1%) 0 (0%)

Other 1 (4%) 1 (0%) 4 (4%)

Gender <.004*

Male 22 (92%) 357 (87%)

69 (73%)

Female 2 (8%) 53 (13%)

24 (26%)

*Fisher’s Exact Test evaluated at a 0.05 significance level

Data Quality: Percent Completeness of Work History and Clinical Indicator by Case Status for all Reported Potential

Cases, 1993-2008

Case Status Work History

Clinical Indicator

Total

Yes 192 (100%)

188 (98%)

192

No 42 (30%) 81 (59%) 138

Missing, Insufficient, or Unknown

37 (19%) 73 (37%) 198

Total 271 (51%)

342 (65%)

528

Data Quality: Percent Completeness of Work History and Clinical Indicator By First Reporting Source for all Reported

Potential Cases, 1993-2008

Work History

Clinical Indicator

Total

Hospital 245 (53%)

321 (69%)

466

Emergency Department

4 (29%) 8 (57%) 14

Death Certificate

9 (31%) 7 (24%) 29

Worker’s Compensation

6 (86%) 0 (0%) 7

Physician Report

4 (67%) 2 (33%) 6

Attribute Rating

Attribute Methods Key Findings

Strength+ Poor++ Fair+++ Good++++ Excellent

Simplicity Interviews, Report Review, Accessed database

*Clinical reports are often difficult to interpret*Follow-up interviews are difficult to obtain*Hospital and Emergency reports are obtained through a simple data extraction procedure

++

Timeliness Interviews, Report Review

*Time from diagnosis to Follow-Up (6 to 21 months) ++

Flexibility Interviews *Could include other occupational respiratory diseases with little alteration ++++

Stability Interviews, Report review

*Fully operational during evaluation period (1993 – 2008) +++

Recommendations

• Explore collaboration with Worker’s Compensation

• Focus on obtaining and coding ethnicity as a priority data collection point

• Target the Hispanic workforce for silicosis awareness and education interventions

Recommendations - continued

• More complete occupational information in hospital discharge data would improve timeliness, simplicity and PPV

• Update database forms and tables to improve the completeness of data entry

• Increase physician reporting through outreach efforts

Acknowledgments

New Jersey Department of Health and Senior ServicesEnvironmental and Occupational Health Surveillance Program

Karen Worthington MS, RN, COHN-SDaniel Lefkowitz MS, PhD

Margaret Lumia, MPH, PhDJerald Fagliano MPH, PhD

This report was supported in part by an appointment to the Applied Epidemiology Fellowship Program administered by the

Council of State and Territorial Epidemiologists (CSTE) and funded by the Centers for Disease Control and Prevention (CDC)

Cooperative Agreement Number 5U38HM000414