Perbedaan rerata skor kualitas hidup pada pasien penyakit paru obstruksi kronik (PPOK) dengan gangguan depresi dan tanpa gangguan depresi di Klinik Asma/PPOK RSUP Persahabatan = Mean difference of quality of life scores between chronic obstructive pulmonary disease copd patients who have depressive disorder and without depressive disorder at asthma copd clinic at Persahabatan Hospital