I. Introduction
The full range of disability determination is quite broad and will not be completely covered in this handout. The interested reader is referred to Guides to the Evaluation of Permanent Impairment, published by the American Medical Association, for a more extensive discussion of all aspects of disability evaluation. This handout will be limited to the common causes of disability that an internist is likely to encounter in clinical practice.
There are several caveats regarding disability determination. First, there is an incredible amount of abuse of the disability/worker's compensation system; this is all to often perpetuated by physicians who submit disability forms for patients who are clearly not impaired, just to satisfy the persistent patient. Another source of abuse of the system is from physicians who provide "expert" support for a diagnosis without backing up the diagnosis with accepted objective tests; when working at the Ohio Industrial Commission, I was very disappointed by the number of patients labeled with "asbestosis" who had normal chest x-rays and pulmonary function tests. Second, the various published criteria for qualification for disability are not as specific nor as uniform as they could be; the rating of the degree of impairment differs between the AMA, American Thoracic Society, and the Social Security system.
II. Definitions
Impairment: alteration of an individual's health status that is assessed by medical means. "Impairment" does not necessarily imply "disability".
Disability: alteration of an individual's capacity to meet personal, social, or occupational demands, or to meet statutory or regulatory requirements. Disability is assessed by non-medical means.
Employability: the capacity to travel to and from work, to be at work, and to perform assigned tasks and duties. For a physician to make a decision about employability, the physician must have a detailed job analysis with respect to performance, physical activity, reliability, availability, productivity, expected duration of useful service life, and qualification.
III. Assessment
When approaching a disability evaluation or even just a request for medical records for the purpose of disability evaluation by another physician, it is useful to ask yourself several questions and provide the answers formally and in writing to the requesting agency. The following is a general guideline; it will obviously have to be adapted for any given form submitted to you. A blank form suggested by the AMA is attached at the end of this handout for those situations where information is requested from you but no form is provided.
1. What is the diagnosis? All diagnoses should be listed. For all major diagnoses, you should list the basis for each. As an example, the diagnosis of asbestosis should be based on history of exposure, appropriate latency, chest x-ray abnormalities, and restrictive changes on pulmonary function tests.
2. Is the condition work-related? There are several levels of work-relatedness:
a) Causation: a workplace exposure resulted in a new disease (example - toludine diisocyanate-induced occupational asthma).
b) Aggravation: there was a pre-existing medical condition which did not interfere with work but the employment caused more symptoms, impairment, or disability (example - COPD in a smoking painter with exacerbation by paint fumes).
c) Acceleration: there was a pre-existing condition which would have worsened with time but the rate of deterioration was accelerated by employment (example - degenerative joint disease made worse by repetitive movement in a stone mason).
d) Precipitation: there was a pre-existing condition which became manifest for the first time because of employment (example - an atopic dogcatcher who develops asthma after exposure to dog dander).
In assessing work-relatedness, it is important to assess the time sequence. For example, it would be wrong to attribute immune-mediated, new onset asthma to a workplace exposure if asthma developed within 3 or 4 days of a new job since sensitization requires weeks or months.
It is also necessary to collect as much exposure documentation as required to make an accurate assessment. This is most often done by requesting Material Safety Data Sheets (MSDS) for suspected exposures. Ask any industrial hygiene questions necessary; it is often essential for the industrial commission or other agencies to have a complete assessment of the work environment performed by an industrial hygienist in order to obtain such information. As an example, one cannot assume that a patient with asthma has toludine diisocyanate (TDI)-induced asthma just because he/she works around plastics; an MSDS for TDI would be necessary to substantiate such a diagnosis.
3. Is there evidence of impairment and, if so, how severe is it? It is critical at this level to obtain as much objective data as possible since symptoms alone are often unreliable. When rating impairment, it is optimal to provide a reference for which impairment rating system you are using; in general, I have found the AMA Guides to the Evaluation of Permanent Impairment to be to most useful. This book in the reference section in the main Health Sciences Library and is a useful purchase if you plan on doing any significant disability work in your future practice.
4. What is the type of disability present? Merely being disabled does not mean the patient cannot work. It is useful to be able to make a statement classifying the permanence of the disability:
a) Partial disability: the patient can perform some, but not all, of his/her usual responsibilities. Typical questions the physician should ask him/herself include: Could the patient return to the job if it were modified? Are there any work restrictions? It is important to be very specific in this regard. As an example, I saw a patient for the industrial commission who was receiving permanent disability because of occupational asthma to rat dander (she was a laboratory technician at the University of Cincinnati). She did not have a great desire to work and an immunologist had stated that "...she should not be exposed to allergens, fumes. or dusts." That statement made her virtually unemployable in any occupation. The more appropriate statement would have been: "...she should not be exposed to rodents." She is still on total disability despite my urging to enter her into an industrial rehabilitation program (your tax dollars at work).
b) Total disability: the patient is unable to do the job even with accommodation.
c) Temporary disability: the patient can return to work after recovery of full function (you should give an estimate of the time required).
d) Permanent disability: there is no prospect for further recovery.
IV. Who Grants Disability?
The field of medical disability is extremely confusing, partly because there are a number of definitions of impairment (see above) but even more because there are a number of agencies which can grant disability.
Social Security Disability Insurance is concerned only with compensation of workers who are completely and permanently impaired; there is no provision for partial disability and work-relatedness is not a consideration. The criteria are strict and only about 50% of claimants ultimately receive benefits. These patients are extremely impaired and most patients die within 3 years of benefit receipt.
Worker's Compensation is a state-administered program which has disability criteria which are more liberal than Social Security. Also, Worker's Compensation provides for partial disability; if workers are granted Worker's Compensation, they usually give up the right to sue their employer for damages.
Federally-Managed Programs (such as Veteran's Administration, Black Lung Program, Longshoreman & Harbor Worker's Program, Federal Employees' Compensation Program, etc.) largely resemble the state run Worker's Compensation programs.
Attorneys may ask for disability evaluation in conjunction with litigation against an employer. In this situation, the physician may be asked to be an expert witness for either the plaintiff or the defendant.
It is important to determine which agency is asking you to evaluate the patient since different agencies will require different types of opinions from the physician (eg, some programs want a disability determination whereas other programs want to simply know whether the patient can continue at his/her current job).
Regardless who asks you to do a disability evaluation, be very thorough and keep complete office records since there is a higher than usual chance that you will ultimately have to provide court testimony related to the case. If you do not feel that you are sufficiently "expert" to do a particular disability evaluation, do not hesitate to tell the referring agency so (consider providing them with the names of physicians in your community who could do a satisfactory evaluation or at least tell the agency what type of specialist they need to consult). Both times that I have been required to testify during a court case regarding disability, it has been completely unexpected and 2-3 years after my evaluation - thus the need for a complete written/dictated history and physical exam as well as documentation of your thinking process and opinions regarding the case.
V. Specific Organ Systems
I have limited inclusion to pulmonary and cardiovascular medicine issues. The AMA text also covers impairment definitions for extremity, nervous system, hematopoietic system, visual system, ear/nose/throat, digestive system, urinary system, reproductive system, endocrine system, skin, and mental disorders.
|
Class 1 |
Class 2 |
Class 3 |
Class 4 |
|
|
0% Impairment |
10-25% Impairment |
30-45% Impairment |
50-100% Impairment |
|
|
FVC |
>/= 80% AND |
60-79% OR |
51-59% OR |
</= 50% |
|
FEV1 |
>/= 80% AND |
60-79% OR |
41-59% OR |
</= 40% |
|
FEV1/FVC |
>/= 70% AND |
60-69% OR |
41-59% OR |
</= 40% |
|
DLCO |
>/= 80% |
60-79% |
41-59% |
</= 40% |
|
or |
or |
or |
or |
|
|
mVO2 |
> 25 ml/min/kg |
20-25 ml/min/kg |
15-20 ml/min/kg |
< 15 ml/min/kg |
Questions
1. A 50 year old insulation installer presents for disability evaluation. He had heavy asbestos exposure from age 15 - 45 and also smoked cigarettes, 2 packs/day during the same time interval. On examination, he has a few scattered wheezes. His chest x-ray shows hyperinflation without infiltrates. Pulmonary function studies reveal an FEV1 = 1.6 liters (50% of predicted) without reversibility, FEV1/FVC ratio = 45% of predicted, TLC = 120% of predicted, and diffusing capacity (corrected for hematocrit & lung volume) = 42% of predicted. What is the diagnosis and the degree of impairment?
2. A 45 year old factory worker presents for disability evaluation. Her job in the factory involves electroplating chromium and she has held this position for 20 years. She is a non-smoker and was diagnosed with adenocarcinoma of the lung 18 months previously. She underwent lobectomy and was noted to have all regional and mediastinal nodes cancer free at the time of surgery, 16 months ago. Reports from her oncologist indicate that a chest x-ray, LFTs, bone scan, and chest/liver CT done 1 month ago showed no evidence of metastasis. Her pulmonary function tests reveal an FVC = 90% of predicted, FEV1 = 82% of predicted, an FEV1/FVC ratio = 72% of predicted, and a diffusing capacity = 80% of predicted. What is the degree of impairment? Is the disease work-related?
3. A 42 year old alcoholic accountant was admitted to your service with shortness of breath, orthopnea, and pedal edema. During the hospitalization, his symptoms improved with initiation of diuretics and captopril. When seen in the clinic 4 months later, he is no longer drinking and is symptom free as long as he continues his medications. His BP is 120/80, pulse is 70, has an enlarged and laterally displaced PMI, and has a third heart sound. Chest x-ray shows cardiomegaly without pulmonary edema. A stress MUGA shows an ejection fraction of 40% which does not change during exercise. What is the diagnosis and degree of impairment?
4. A 56 year old machinist has sudden, severe chest pain associated with anterior ST segment elevation and a moderate rise in CK MB levels. She has a strong family history of coronary disease and had a TAH/BSO at age 34 for endometriosis. She has an uneventful recovery and is discharged on metoprolol, aspirin, and PRN nitroglycerin. Three months later, she tells you that she has occasional chest pain and has used about half of her nitroglycerin bottle. You perform a stress EKG test and find that at about 6 METS on a Bruce protocol, she develops chest pain and 2 mm anterior ST depression, both of which are promptly relieved with a single sublingual nitroglycerin. What is the diagnosis and is it work related? What is the degree of impairment?
5. A 36 year old sales manager has a long history of hypertension. There is a strong family history of hypertension in young adults. He has had prior evaluations which were negative for pheochromocytoma, renal artery stenosis, and Cushing's syndrome. He is asymptomatic but has had diastolic BPs > 100 for two years despite several drug regimens. He is presently taking propranolol, minoxidil, and lasix. An S4 is consistently present on physical exam. His EKG shows a 25 mm R wave in leads I and aVL, a 35 mm R wave in leads V5 and V6, a 35 mm S wave in V1 and V2, and left axis deviation. What is his level of impairment?
6. A 60 year old brick mason presents with worsening dyspnea on exertion over the past 4 years. He has a 38 pack-year history of smoking. On physical examination, he has crackles diffusely over both lungs. There are extensive reticulonodular infiltrates in the upper portions of both lungs. Pulmonary function tests show an FEV1 = 55% of predicted, FVC = 53% of predicted, FEV1/FVC = 88%, TLC = 60%, diffusing capacity = 55% of predicted. You order a pulmonary exercise study and find that he reaches 60% of his predicted maximum heart rate, has a VO2 max = 12 ml/(kgomin), and desaturates to 80% SaO2 at peak exercise. What is the diagnosis and what is the degree of impairment?
Answers
1. This patient has emphysema due to cigarette use and has no evidence of asbestosis. He is impaired to a level of Class III (30 - 45% of the body as a whole) because of his emphysema.
2. This patient is not impaired. She was classified as severely impaired for the 1 year following her surgery (all patients with lung cancer are automatically considered severely impaired at the time of diagnosis and for 1 year after definitive treatment; if they develop recurrent cancer, they again automatically become severely impaired). Her pulmonary function tests are normal enough to put her into Class I (0% impairment of the body as a whole). Her lung cancer can be assumed to be caused by chromium exposure (chromium is a known carcinogen).
3. This patient has alcoholic cardiomyopathy not related to his occupation. He is impaired at 15 - 25% of the body as a whole because he is asymptomatic, has impaired LV function by MUGA and requires medication to remain symptom-free.
4. This patient has coronary disease not related to her occupation (although you would be surprised at how many patients try to attribute their MI due to atherosclerosis to a stressful work environment). She is impaired at a level of Class 3 (30 - 50% of the body as a whole) because of a documented MI plus angina requiring medications to control and developing after moderately heavy exertion (functional class II [note that the functional class designation, as established by the NY heart association, is distinct from the impairment classification used in disability determination - an often confusing point]).
5. This patient has hypertensive cardiovascular disease with left ventricular hypertrophy. He is impaired at Class 3 (30 - 50% of the person as a whole) because of persistently elevated diastolic BP despite medications and evidence of LVH by physical exam and EKG.
6. The diagnosis is silicosis. He is impaired to a level of Class 4 (50 - 100% of the whole person) based on his very low VO2 max.
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