One of the most common LTD denial strategies involves pre-existing condition exclusion clauses. Group LTD policies typically exclude disabilities arising from, caused by, or resulting from pre-existing conditions that were diagnosed or treated within a specified period (usually 3–12 months) before coverage commenced. Insurers use medical records — sometimes gathered without claimants’ full awareness — to identify historical diagnoses that can be characterized as causing the current disability.
Ontario courts apply established principles of insurance contract interpretation: exclusions, as exceptions to coverage, are construed narrowly. The insurer bears the burden of establishing the exclusion applies. A prior diagnosis or treatment episode does not automatically trigger exclusion — the insurer must establish a causal connection between the pre-existing condition and the specific disability claimed. Prior back pain three years ago does not exclude an LTD claim arising from a completely different spinal condition today.
The aggravation principle: Where an accident or workplace incident aggravates or accelerates a pre-existing condition beyond its natural progression, the disability may still qualify for benefits depending on policy language. The thin skull principle informs causation analysis in insurance law. Predisposition to a condition does not mean the disability is “pre-existing” in the exclusionary sense.
The most effective protection is a treating physician who clearly distinguishes the current disabling condition from any historical conditions and articulates why they do not constitute a pre-existing condition within the policy definition. Medical records that accurately document the history and trajectory of the claimant’s health — without conflating distinct conditions — provide the clearest foundation for defeating an exclusion argument.