Persistence' Focus: Treatment and Medicolegal Issues 3rd Jack Pepys Workshop

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Persistence. Focus Treatment and Medico-legal
Issues3rd Jack Pepys Workshop

• Susan M Tarlo
• University of Toronto
• University Health Network and
• Gage Occupational and Environmental Health Unit

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Disclosures

• Patients are seen for medical assessment at the
  request of the Ontario Workplace Safety and
  Insurance Board (WSIB), approx 1 new patient per
  week
• Patients referred by other physicians may have
  claims submitted by me to WSIB
• Files being appealed from WSIB may be reviewed
  for an independent medical opinion from WSIAT
• Research funding has been received from WSIB RAC

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From 100 questions/needstreatment/medicolegal
77. Despite strong medical advice to
discontinue exposure to a work sensitizer, some
patients with OA continue to work in the same
environment with the same or reduced exposure.
What is the value of inhaled steroids in such
patients? 78. Subjects with OA are exposed to
common allergens after being removed from work.
In the case of OA due to low molecular weight
agents, is there cross-reactivity with other
common environmental chemicals that resemble the
causal agent? 79. In aiming to assess the
efficacy of intervention in work-related asthma,
a problem in the design of post-intervention
studies is that there is usually no control
group. How can this study design problem be
overcome?
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Current management of sensitizer-induced OA
during/post diagnosis

• Initiate appropriate compensation claim (early)
• Control the asthma - throughout
• Evaluate and control exposure to relevant
  non-occupational triggers
• Asthma medications as per guidelines
• Evaluate appropriate work accommodation
• For the patient
• Consider co-workers and possible work
  intervention to protect other workers

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Evaluate appropriate work accommodationfor the
patient when the sensitizer is known

• Where possible, completely avoid further exposure
  to the relevant sensitizer after diagnosis
• If impossible for socio-economic reasons, reduce
  exposure compensation issues may be relevant
  here if this is the required approach, either
  pending a compensation claim or for other reasons
  such as lack of eligibility for compensation,
  there must be careful medical monitoring, and
  further intervention if asthma is worsening

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Exposure ManagementAHRQ Evidence Report 129,
Nov 2005, Beech et al

• 52 cohort studies
• Due to vagaries of reporting, statistical
  analyses of published studies not feasible
• Graphic display of results suggested worse
  outcomes (FEV1 and methacholine responsiveness)
  for those remaining at work vs those removed. No
  clear difference in trend for HMWt vs LMWt
  sensitizers

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Black HMWt WhiteLMWt Greymixed/unknown
PC20 changes
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Possible measures to avoid/limit exposure

• Best to worst options
• Avoidance complete - change of process, e.g.
• non-latex gloves, enzyme change, paint change
• Change of work area/workplace (with review of
  exposures in new area)
• Partial reduction e.g. low-protein, low powder
  latex
• Move to low-exposure area
• Improved occ hygiene measures, e.g.
  ventilation/exhaust
• Improve resp protection

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Outcome with removal vs continued exposure
(Moscato et al Chest 99)

• 25 with OA confirmed by challenge, followed for
  1y
• 13 left exposure significantly worse asthma at
  diagnosis, FEV1 and PD20
• At 1y those who left had improved more than those
  who stayed decreased medication needs vs
  increased needs in those who stayed
• However only those who left had a loss in income
  (gt25 median loss)

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Inhaled steroids for those who cannot avoid
exposure (Marabini et al Chest 03)

• 20 subjects with OA (mean sx 13/-13y), still
  working. 12 moderate, 8 mild
• 3 y f-up, protective equipment as able
• 10 retired/changed jobs (significantly younger
  than those who stayed). Only 2 cleared
• Those who stayed were treated with high dose
  inhaled steroids and bronchodilators
• No statistically significant change over the 3y
  in spirometry, bd needs for those who stayed,
• PD20 mg yearly mean 1.4, 1.3, 1.2, 0.8 (NS)
• Findings limited by small numbers. Trends to
  decline in PD20. ?? Whether applicable to those
  with earlier diagnosis

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Reduced exposure for NRL-OAAsthma symptom scores
(ASS) and histamine PC20
Vandenplas et al JACI 2002
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Monitor asthma closely with occupational changes
(changes in exposures/job)

• When the sensitizer is unknown and/or may be
  present in a new environment
• When there may be cross-reacting agents in the
  environment where the patient is moved to
• When the exposure is reduced but not eliminated
• Symptoms/medications/pulmonary function
  parameters/? NO, ? induced sputum

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Cross-reacting agents

• Other than similar chemical sensitizers, e.g.,
  other diisocyanates in or out of the workplace,
  little published data on agents cross-reacting
  with work-sensitizers
• - a few older reports of colophony and
  non-occupational pine products
• ? Any current research in this area

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Pharmacotherapy

• Inhaled steroids 2 older clinical trials
  suggested benefit, no recent trials
• No recent studies of pharmacotherapy among those
  remaining in exposure

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Immunotherapy?

• Small trials of immunotherapy have been reported
  for NRL allergy and asthma
• Benefit found more for nasal/eye symptoms than
  for asthma to date (Sastre et al, JACI 03)
• Sublingual treatment appears to be better
  tolerated but local reactions(89 patients) and
  systemic reactions (46 patients) were still
  common (Cistero Bahima et al J Invest All Clin
  Immunol 04)
• Not considered standard treatment for OA

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Immunotherapy with other agents

• Beekeepers with anaphylaxis ( asthma) respond
  well to venom immunotherapy (Muller, Curr Opin
  All Clin Immunol 2005)
• Armentia 90 assessed 30 bakers with wheat
  immunotherapy (20 active, 10 placebo) with
  significant benefit no recent studies
• Common allergens, cat, pollen, not specifically
  addressed in OA
• Omalizumab not reported as yet for OA

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Some reasons for poor medical outcome

• Severe asthma at diagnosis
• Late diagnosis (2? to patient or physician),
  delay or no compensation leading to prolonged
  exposure
• Occupational factors
• Ongoing exposure to the work sensitizer or
  cross-reacting agents (known or unknown) at work
  or in other environments
• Workplace irritant exposure aggravating asthma
• Other contributing factors
• Non-occupational allergen exposure/ irritants
• GERD, VCD, non-asthma causes of symptoms

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Compensation/medicolegal issues

• Different systems in different provinces, states,
  countries
• Some issues likely to be common in many regions
  where others may be specific
• Criteria for acceptance may differ - e.g., need
  for SIC for OA, acceptance of WEA
• Process might contribute to persistence of
  asthma/disability no identified published data
  on this
• More likely if workers continue exposure
  because
• Ineligible for compensation
• Reluctance to apply for a claim no data
• Delays in a claim decision could be years

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E.g., Ontario WSIB www.wsib.on.ca

• Began 1915 as WCB
• Financed by employer premiums (adjusted by risk)
• No-fault collective liability workers give up
  their right to sue
• 1998 Changed name to WSIB and mandate changed to
  include promoting prevention of work-related
  injuries and illnesses. It now also oversees
  Ontarios system of workplace safety education
  and training, and supports research via an
  independent Research Advisory Council and Centres
  for Research Expertise, e.g. CREOD.
• Mandate includes disability benefits, monitoring
  quality of healthcare, and assisting in early
  safe return to work

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Ontario WSIB

• Policy In determining a claim the decision shall
  be made in accordance with the real merits and
  justice of the case. ..When the evidence for or
  against the issue is approximately equal in
  weight, the issue shall be resolved in favor of
  the person claiming benefits (not to be used as a
  substitute for evidence).
• Decisions on claim acceptance and compensation
  made by claims adjudicators they are usually
  assigned by work sector rather than by
  disease/injury. They can get advice from the
  complex case unit WSIB physicians who may
  request additional external independent medical
  assessments, e.g., from the occupational disease
  specialty program. WSIB pays for costs of
  assessments/investigations.

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Support provided for accepted OA claims

• Economic loss - 85 provided for limited time
  after claim accepted if further job is feasible,
  supplement if lower-paying job obtained
• Cost of medications/medical devices
• Non-economic loss disability (usually assessed
  at the time of considered maximum medical
  recovery, e.g. often 1-2 y after an OA claim is
  accepted). Includes disability from asthma plus
  disability from sensitization if present.
• Training for new work if approved labor market
  re-entry skills, re-training (secondary/post
  secondary ed)
• Examples 18 y old baker, 45 y old plasma welder

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Work-exacerbated/aggravated asthma

• Policy In cases where the worker has a
  pre-accident impairment and suffers a minor
  work-related injury or illness to the same body
  part or system WSIB considers entitlement to
  benefits on an aggravation basis.
• Generally entitlement is for the acute episode
  only and benefits continue until the worker
  returns to the pre-accident state.
• Entitlement is not limited when there is no
  pre-accident impairment or if the severity of the
  exposure/accident on its own would have resulted
  in additional impairment i.e. potential for
  permanent aggravation
• Aggravation is the effect that the injury/illness
  has on pre-accident impairment, requiring
  healthcare and/or leading to loss of earning
  capacity can include permanent impairment

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Compensation issues

• Not all workers are covered
• Processes for decisions and levels of
  compensation differs widely between and even
  within countries
• Process can be complicated and time-consuming for
  workers and physicians forms for
  worker/physician/workplace
• Decisions can take months to years
• Workers with OA often do not have skills to
  transfer to other similar-paying occupations
• Job-market re-entry programs may provide some
  skills but will usually not find replacement
  work, and self-found jobs may pay less than
  former work

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More compensation issues

• Workers may lose non-compensated benefits from
  previous job, e.g. dental plans, general
  medication coverage
• Even with accepted workers compensation claims,
  significant socio-economic loss is reported
• Effects of having a previous compensation claim
  on chance of employment, not published
• Some workers are reluctant to accept advice to
  initiate a compensation claim and prefer to
  continue working with OA as long as possible
  may lead to less reversibility and greater long
  term asthma morbidity
• Suggests that further improvements are needed for
  compensation issues

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Ontario WSIB appeals

• Worker or workplace can appeal decision to WSIB
  issues of stress, income loss
• Next decision can be appealed to an independent
  Workplace Safety and Insurance Appeals Tribunal
  an agency within the Ontario administrative
  justice system who may ask for further
  independent medical review

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Conclusions

• Early diagnosis and removal from further exposure
  (for sensitizer-OA) offers best medical outcome -
  but often at a significant socio-economic cost
  despite workers compensation systems. Other
  management options (e.g. greatly reduced exposure
  for NRL), are an alternative for some agents and
  are selected by other workers with OA against
  medical advice.
• Immunotherapy may benefit some patients but few
  allergens have been assessed and monoclonal anti
  IgE has not been assessed. Pharmacotherapy
  reduced exposure has not currently been proven of
  benefit
• The effects of compensation systems on asthma
  persistence have not been documented