Effects of different body positions on peak expiratory floe rate in patient with types 2 diabetes mellitus and non-diabetic mellitus individuals: a comparative study

Background: Type 2 Diabetes Mellitus (T2DM) is a chronic metabolic disorder that may adversely affect pulmonary function through mechanisms such as respiratory muscle weakness, microvascular changes, altered connective tissue properties, and chronic metabolic disturbances. Peak Expiratory Flow Rate (PEFR) is a simple and clinically useful measure of expiratory airflow. Body position may influence respiratory mechanics and expiratory performance; however, the effect of sitting and standing positions on PEFR in individuals with T2DM compared with non-diabetic individuals remains unclear. Aim: To evaluate the effect of different body positions on Peak Expiratory Flow Rate (PEFR) in patients with Type 2 Diabetes Mellitus and compare the findings with non-diabetic individuals. Methods: A comparative cross-sectional study was conducted on 180 participants aged 30–60 years, comprising 90 individuals with Type 2 Diabetes Mellitus and 90 non-diabetic individuals. Participants were assessed for PEFR in sitting and standing positions using a peak flow meter. Three measurements were obtained in each position, and the highest value was recorded. Participants were selected according to predefined inclusion and exclusion criteria. The effects of diabetic status, body position, and gender on PEFR were analysed using three-way analysis of variance (ANOVA), followed by Tukey-adjusted post hoc comparisons where appropriate. Results: Non-diabetic participants demonstrated a significantly higher mean PEFR than diabetic participants, with mean values of approximately 359 L/min and 319 L/min, respectively (F = 25.76, p < 0.001). A significant main effect of gender was also observed, with males demonstrating higher mean PEFR than females (398 ± 80.3 L/min vs. 297 ± 70.7 L/min; F = 100.64, p < 0.001). In contrast, body position did not produce a statistically significant difference in PEFR between sitting and standing positions (F = 1.36, p = 0.245). None of the interaction effects, including Group × Position, Group × Gender, Position × Gender, and Group × Position × Gender, were statistically significant (p > 0.05). Post hoc analysis further demonstrated consistently higher PEFR values among males compared with females, whereas differences between sitting and standing positions were generally not significant. Conclusion: The findings indicate that Type 2 Diabetes Mellitus is associated with significantly reduced PEFR compared with non-diabetic individuals, while gender has a significant influence on PEFR, with males demonstrating higher expiratory flow rates than females. However, the sitting and standing positions did not significantly affect PEFR in the study population. Therefore, either sitting or standing may be used for PEFR assessment in ambulatory adults when the measurement position is standardized and consistently documented. The findings highlight the importance of considering diabetic status and gender when interpreting PEFR values.