According to the CDC, 11.6 percent of Americans have Diabetes mellitus, nearly half have hypertension, and 42% are obese (1). These and many other diseases are often comorbid conditions afflicting our working population. These not only put workers at greater risk of injury, but also hinder optimal treatment and delay return to work.
Common Comorbidities
The most common comorbidities in the working population include obesity, COPD, diabetes, hypertension, and drug abuse (2). These chronic conditions may predispose to injury or hinder or delay effective treatment. According to the Centers for Disease Control and Prevention (CDC), nearly 52% of Americans have been diagnosed with at least one chronic condition (1). The presence of one chronic health issue often elevates the risk of developing another, such as diabetes, obesity, or hypertension, leading to more complex and costly Workers’ Compensation claims.
Metabolic syndrome is a cluster of cardiometabolic risk factors associated with increased risk of multiple chronic diseases, including cancer, diabetes, and cardiovascular disease. An individual has metabolic syndrome when at least three of the following are present: increased waist size, elevated blood triglycerides, low HDL cholesterol, high blood pressure, and elevated blood sugar. According to the National Heart, Lung, and Blood Institute, 1 in 3 adults in the United States have metabolic syndrome (3). Identifying and reducing cardiometabolic risks driven by obesity remains a healthcare challenge. It has been studied that GLP-1 agonists (glucagon-like peptide 1 receptors), along with a combination of exercise, reduced metabolic syndrome severity, abdominal obesity, and inflammation (4). Improved control of these conditions can lead to better overall health for injured workers, potentially reducing complications related to their injuries and comorbidities. Better metabolic control can also improve wound healing and recovery times, translating to faster rehabilitation and reduced time away from work for injured workers.
Risk factors associated with injury
Data collected from the National Council on Compensation Insurance (NCCI) shows that over 25% of claims with an obesity comorbidity diagnosis are for sprains and strains (2). Obesity poses a risk factor for diseases of the musculoskeletal system, and the same NCCI study also found that obese workers were more likely to become permanently disabled.
Back pain is the leading cause of global years lived with disability. There is a significant association between back pain and smoking, with 36.9% of current smokers experiencing a form of back pain (5). Nicotine can alter the size of blood vessels and the ability for the body to adapt, causing increased damage to the ligaments as well as muscles within the spine region. Furthermore, smoking can cause breakdown at the discs of the spine due to the lack of nutrient exchange, specifically where the bone meets the spine disc. This suggests that there may be a biological gradient associated with exposure to smoking cigarettes and back pain in Americans.
Carpal tunnel syndrome (CTS) is the most common compression neuropathy in the general population and is frequently encountered in individuals with Types 1 and 2 diabetes. Individuals with neuropathy due to diabetes have a higher risk of peripheral nerve compression disorders (6). Diabetes patients are also at an increased risk for traumatic injuries and falls due to hypoglycemia causing compromised psychomotor skills, visuospatial functions, and rapid information processing, as well as the neurogenic (shakiness, tachycardia, anxiety) and neuroglycopenic (weakness, dizziness, impaired vision) symptoms of hypoglycemia (7).
Hypertension leads to microvascular disease through mechanisms involving endothelial dysfunction, structural changes in blood vessels, and microvascular rarefaction. These changes impair blood flow and oxygen delivery to various soft tissues, resulting in complications such as poor wound healing, muscle fatigue, neuropathy, kidney damage, retinopathy, and microvascular angina (8). Managing hypertension is crucial to prevent these microvascular complications and maintain the health of soft tissues throughout the body.
Disruption of Treatment
Appropriate treatment for injuries is often delayed or hindered by comorbidities. For instance, steroid injections are contraindicated in poorly controlled diabetes, and carry higher risk in anyone with diabetes due to their hyperglycemic effects. Morbid obesity increases the risk of elective surgeries, and a BMI greater than 37 is associated with increased complications (9). Therefore, many surgeons opt to recommend medical optimization prior to surgery. Tobacco use is associated with chronic pain, greater risk of wound complications, and poor outcomes of surgical treatment (10). Many surgeons require proof of cessation of tobacco prior to elective surgery via serum nicotine levels.
Even with nonoperative treatment, an obese worker is likely to miss 13 more days of work compared to a non-obese worker following an injury (11). If this worker also has diabetes, their recovery time could be extended even further due to complications like poor wound healing.
Apportionment with Comorbidities
When an employee with comorbidities suffers a workplace injury, QMEs must differentiate between the impact of the preexisting conditions and the work-related injury. An obese employee who sustains a knee injury will experience more severe symptoms and a longer recovery period due to the added strain on their joints from their weight. When a QME is considering apportionment, he or she will need to consider causation of the disability, and not simply risk factors, according to Labor Code §4663(a). Some QMEs argue for obesity as an apportionable condition, as it can lead to causation of disability. Even without injury, patients who have longstanding obesity will likely develop degeneration at an accelerated rate from the weight placed on their joints, and apportioning to this is not speculative.
Chronic, uncontrolled diabetes is a microvascular disease that will lead to increased risk of peripheral nerve injury, including peripheral neuropathy and carpal tunnel syndrome. There does remain some risk of these injuries even in well-controlled diabetes, including carpal tunnel syndrome. Evidence of a biological cause of disability due to carpal tunnel syndrome as opposed to a pure industrial injury would be unilateral symptomatic carpal tunnel syndrome following a brief exposure to injurious repetitive tasks with EMG/NCS evidence of bilateral carpal tunnel syndrome. In the presence of inflammatory arthritis such as rheumatoid arthritis, lupus, or psoriasis, or seronegative spondyloarthropathies such as ankylosing spondylitis, many QMEs argue for apportionment of the cause of disability. While causation of injury cannot be apportioned, allowing for treatment of superimposed industrial injuries, causation of disability is, and this affects the final settlement.
In the Lindh decision, also known as the City of Petaluma v. WCAB, it was determined that apportionment is allowed to asymptomatic preexisting conditions that are a risk factor to injury. A police canine officer (Lindh) hit his head several times during training with a police dog and subsequently lost vision in one eye. During his treatment, it was discovered that he had an underlying blood circulation condition that could contribute to his blindness, but was completely asymptomatic. The QME opined that 85% of his overall permanent disability was nonindustrial due to his underlying condition, citing that it was unlikely that Lindh would have lost his vision in his eye if not for the underlying condition. The WCAB initially rejected any apportionment to the underlying abnormality, and the Court of Appeal subsequently overturned that decision.
Comorbidities may create risk of industrial injury, impact the efficacy and duration of treatment on injured workers, and be considered in the apportionment of disability. The general poor health of the average American is reflected in the working population and presents additional challenges to the treating physicians and forensic expert witnesses helping to settle disputes in these cases. While the comorbidities may not be ignored, an unbiased physician must follow the labor code, case law, and medical ethics in making determinations of treatment options and factors of settlement.
References
- Boersma P, Black LI, Ward BW. Prevalence of Multiple Chronic Conditions Among US Adults, 2018. Prev Chronic Dis 2020;17:200130. DOI: http://dx.doi.org/10.5888/pcd17.200130
- Laws, Chris, and David Colon. “Comorbidities in Workers’ Compensation.” ncci.com, October 2012. https://www.ncci.com/Articles/Pages/II_research-brief-comorbidities-in-workers-compensation-2012.pdf.
- “What Is Metabolic Syndrome?” National Heart Lung and Blood Institute. Accessed May 23, 2024. https://www.nhlbi.nih.gov/health/metabolic-syndrome#:~:text=Metabolic%20syndrome%20is%20common%20in,3%20adults%20have%20metabolic%20syndrome.
- Sandsdal, R.M., Juhl, C.R., Jensen, S.B.K. et al. Combination of exercise and GLP-1 receptor agonist treatment reduces severity of metabolic syndrome, abdominal obesity, and inflammation: a randomized controlled trial. Cardiovasc Diabetol 22, 41 (2023). https://doi.org/10.1186/s12933-023-01765-z
- Green BN, Johnson CD, Snodgrass J, Smith M, Dunn AS. Association Between Smoking and Back Pain in a Cross-Section of Adult Americans. Cureus. 2016 Sep 26;8(9):e806. doi: 10.7759/cureus.806. PMID: 27790393; PMCID: PMC5081254.
- Zimmerman M, Gottsäter A, Dahlin LB. Carpal Tunnel Syndrome and Diabetes-A Comprehensive Review. J Clin Med. 2022 Mar 17;11(6):1674. doi: 10.3390/jcm11061674. PMID: 35329999; PMCID: PMC8952414.
- El-Menyar A, Mekkodathil A, Al-Thani H. Traumatic injuries in patients with diabetes mellitus. J Emerg Trauma Shock. 2016 Apr-Jun;9(2):64-72. doi: 10.4103/0974-2700.179461. PMID: 27162438; PMCID: PMC4843569.
- Zhou W, Brown JM, Bajaj NS, Chandra A, Divakaran S, Weber B, Bibbo CF, Hainer J, Taqueti VR, Dorbala S, Blankstein R, Adler D, O’Gara P, Di Carli MF. Hypertensive coronary microvascular dysfunction: a subclinical marker of end organ damage and heart failure. Eur Heart J. 2020 Jul 1;41(25):2366-2375. doi: 10.1093/eurheartj/ehaa191. PMID: 32221588; PMCID: PMC7327534.
- Ri M, Aikou S, Seto Y. Obesity as a surgical risk factor. Ann Gastroenterol Surg. 2017 Oct 28;2(1):13-21. doi: 10.1002/ags3.12049. PMID: 29863119; PMCID: PMC5881295.
- Audet MA, Benedick A, Vallier HA. Tobacco smoking is associated with more pain and worse functional outcomes after torsional ankle fracture. OTA Int. 2022 Jan 19;5(1):e175. doi: 10.1097/OI9.0000000000000175. PMID: 35059563; PMCID: PMC8765575.
- Glennon, Kevin. “Obesity’s Impact on Workers’ Compensation.” Risk Management Magazine, November 1, 2014. https://www.rmmagazine.com/articles/article/2014/11/01/-Obesity’s-Impact-on-Workers-Compensation-.