Backdrop: Coronary artery disease (CAD) remains a leading cause of morbidity and mortality, with lifestyle factors playing a key role in disease progression and recurrence. Objective: To evaluate the effect of structured lifestyle modifications on biochemical parameters in patients with established CAD. Methods: A prospective interventional study was conducted involving CAD patients who underwent lifestyle changes over a 6-month period. Interventions included dietary adjustments, regular physical activity, and cessation of smoking and alcohol. Biochemical markers—namely Thyroid Function Test (T3, T4, TSH) and liver enzyme ratio (ALT/AST ratio) were assessed before and after the intervention. Discussion: The majority of participants were aged 51–70 years, predominantly male, and urban dwellers. Post-intervention data revealed significant improvements in thyroid hormone levels (normalization of TSH, T3, and T4), a favorable shift in the ALT/AST ratio indicating better liver function, and marked reductions in hs-CRP, uric acid, and fasting blood sugar levels. These biochemical improvements reflect reduced systemic inflammation, better metabolic regulation, and lowered cardiovascular risk. Conclusion: Lifestyle modifications yielded substantial improvements in biochemical risk factors in CAD patients, including thyroid function and liver enzyme profiles. Non-pharmacological interventions are vital for secondary prevention and the enhancement of long-term cardiovascular health.

Coronary artery disease, Thyroid Function Tests, ALT/AST ratio, lifestyle modification