Introduction: COPD is a complex disease characterized by chronic respiratory symptoms, abnormalities of lung structure and function with frequent comorbidities that affect the patient's quality of life. Coughing and expectoration are symptoms that lead to exacerbations and deterioration of lung function.

Objective: Aim of research was to examine the differences between COPD patients in different climatic conditions: Mediterranean and continental parts of Croatia.

Methods: 136 COPD patients were included; 67 form Mediterranean and 69 from continental part of Croatia. Out of 136, mean age 71 years, 95 (70%) were male and 41 (30%) female, mean 45 pack/years. Spirometry with a bronchodilation test, CO diffusion and lung CT scan were performed. Quality of life was analyzed with questionnaires SF-36 and SGRQ, symptoms were assessed with CAT and dispnea with mMRC scale.

Results: There were no statistically significant differences in demographic characteristics between the two groups. Cough was significantly more prominent in continental group (n=59; 86%) vs Mediterranean group (n=31; 46%; p<0,001), as same as expectoration (n=52; 75% vs n=21; 31%; p<0,001). There was more emphysema in the Mediterranean group (n=47; 74% vs n=28; 68%; p<0,001) and a better quality of life. Patients in continental part had more comorbidities; CV diseases (n=56; 81% vs n=28; 42%; p<0,001) and depression (n=22; 32% vs n=9; 13%; p<0,01).

Conclusion: Our research has shown clinically interesting differences in symptoms and comorbidities of COPD related to the climate which could be the result of differences in air temperature and moisture, the effect of sun exposure and anti-inflammatory effect of vitamin D.