PULMONARY FUNCTION DERANGEMENT IN PATIENTS OF DIABETES MELLITUS

1. Professor Department of Medicine, RNT Medical College, Udaipur, Rajasthan. 2. Post Graduate Resident Department of Medicine, RNT Medical College, Udaipur, Rajasthan. 3. Senior Professor Department of Medicine, RNT Medical College, Udaipur, Rajasthan. ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History Received: 31 May 2020 Final Accepted: 30 June 2020 Published: July 2020 Background: Diabetes mellitus is a metabolic disorder characterized by hyperglycaemia resulting from defects in insulin secretion, action or both. Nonenzymatic glycosylation induced alteration of lung connective tissue is the most likely mechanism underlying the mechanical pulmonary dysfunction in diabetic subjects. The present study evaluates the impact of diabetes mellitus on pulmonary function in this cross sectional study of population. Aims and objectives: To evaluate the impact of diabetes mellitus on pulmonary functions by comparing with control groups. Materials And Method: All patients presenting in Department of Medicine, R.N.T. Medical College, Udaipur who were proved cases of type 2 diabetes mellitus were included in this study from September 2017 to September 2018. 50 patients and 50 controls with matched age and sex were included. All patients were interviewed, detailed history was taken with respect to risk factors and detailed physical examination was carried out and appropriate investigations were carried out. Results: FVC among diabetics was low with a mean of 2.46 as compared to controls with mean of 2.99 with p value of 0.001 which is statistically significant. FEV1 was reduced in cases with mean of 2.0542 compared to controls with mean of 2.4906 with a p value of 0.001 being statistically significant. FEV1/ FVC was higher in diabetic group with mean value of 0.8304 as compared with controls with mean value of 0.8316. Conclusion: Diabetic patients show reduced lung function with a restrictive pattern of lung disease on the Spirometry.


ISSN: 2320-5407
Int. J. Adv. Res. 8(07), 1817-1823 1818 There are histopathological changes seen in lungs of diabetics such as thickened alveolar epithelial and pulmonary capillary basal lamina leading to reduced pulmonary elastic recoil and lung volume. Nonenzymatic glycosylation induced alteration of lung connective tissue is the most likely mechanism underlying the mechanical pulmonary dysfunction in diabetic subjects 3 .
This suggests that lung is also a target organ 4 . Spirometry is a widely used pulmonary function test (PFT), ideally suited to describing the effects of obstruction or restriction of lung function. The spirometric parameters have gained more popularity when it has been reported that impaired Forced Vital Capacity (FVC) and Forced Expiratory Volume in 1 sec (FEV1) are emerging novel risk factors for diabetes mellitus 5 . In spite of this, spirometry is not used routinely as part of a management system in diabetic patients. Its role is neitherfully explored, nor fully utilized to achieve quality of life when managing diabetesmellitus.
The present study is undertaken to evaluate the impact of diabetes mellitus and pulmonary function in this cross sectional study of population. Data were collected by using performa meeting the objectives of the study. Purpose of the study was carefully explained to patients and consent was taken.

Materials And Method:-
All patients were interviewed, detailed history was taken with respect to risk factors and detailed physical examination was carried out and appropriate investigations done which included complete blood counts, fasting blood sugar, post-prandial blood sugar, HbA 1C, X ray chest (PA view), Spirometry (FVC, FEV1, FEV1/FVC values recorded) Pulmonary function tests(PFT) of diabetic patients and controls were compared by applying student's unpaired t-test while correlations between FVC , FEV1 , HbA1C and duration of illness in diabetic patients were analyzed by applying Pearson's co-efficient.

Results:-
A total of 100 subjects were included in the present study 50(29 males and 21 females) of them were diabetics and the other 50(32 males and 18 females) were non diabetic controls. 50% cases belonged to the age group of 40-49 years, 24% to 50-59 years and 26% to 60 and above age group. Similar distribution was assured in controls with 38%, 34% and 28% respectively in the three age groups. The mean age in both groups being 51.43 The glycemic parameters which included the FBS, PPBS and HbA1c are 204.86mg/dl, 254.30mg/dl and 8.1474% respectively for cases and 96.58, 127.04 and 4.802 respectively for controls. (Table I) Body mass index (BMI) of cases and controls were comparable with mean among study group being 24.407 and in controls its value was 25.18. The difference was not statistically significant with a p value of 0.209.
The spirometric values in both groups can be seen summarized in Table II The study also tried to correlate the severity of impairment of the lung function test with duration of diabetes mellitus. Two groups were taken-one with disease duration <5 years and other >5 years. The glycemic parameters of the two groups are shown in Table III. It was observed that glycemic control was better in long term diabetics(>5years duration) than the newly diagnosed ones(<5 years) It was also observed that the values of FEV1 and FVC were better in long term diabetics than newly diagnosed ones (Table IV)

Discussion:-
Present study was undertaken to assess ventilatory function of subjects with diabetes mellitus in comparison to subjects without diabetes. Larger population-based studies have been more consistent, demonstrating reduced pulmonary functions in patients with an elevated plasma glucose level and a diagnosis of DM.
The present study is in agreement with the previous study [6][7][8][9][10] (Table V) and the inference drawn from this study is similar to those studies. The study proves the hypothesis of reduced FVC in diabetics compared to their age, sex and BMI matched controls.
The study also shows coherence the study of Walter E Robert et al 11  The key aspect of the present study is the observation that although diabetic subjects had low FVC compared to controls the group of diabetics with diabetes mellitus less than 5 years had lower FVC than in those with duration > 5 years. FVC in diabetics with <5 years duration(22 study subjects) was 2.30, much lower than controls(2.98) but in diabetics >5 years(28 study subjects) it was 2.70 only marginally(but significantly) less than the controls.. These results were contrary to the study done by Sultan 7 where there was no significant reduction in FVC in diabetics of <5 years duration(FVC=3.68) and a linear fall in the values of FVC in diabetics with 5-12years duration(FVC=3.16) and >12 years duration (FVC=3.11) compared to controls(FVC=3.74). (Figure 1) When the natural history of disease was compared on the time line with regard to FEV1we still observed the same improving pattern with diabetics >5years(comparison shown in table VII and figure II) . While unlike FVC , FEV1 in Sultan's7 study showed similar pattern to that of ours with a decline in diabetics <5years duration and then improving in 5-12 years duration diabetics. But Sultan's study found that beyond 12 years of duration of diabetes the FEV1 declined again. This result may have not been seen in our study due to not so long (more than 10 years) follow up of thediabetics.
Masmoudi and Zouari13 concluded that pulmonary volumes impairments are slightly more marked with diabetes mellitus duration especially after 10 years. Barret-Connor E et14 also found that pulmonary function in older adults is altered in subjects with diabetes mellitus with duration more than 10 years. The improvement in respiratory function can be hypothesized to a better metabolic control.Our results are similar to those of Lange P 15 who found that the decrease of ventilator capacity is more marked at the beginning of diabetes mellitus. Davis A Wendy et al 16 who studied the glycemic exposure and associated reduced pulmonary function in type 2 diabetes found a decrease in FVC 1820 at an annual rate of 68ml/year and FEV1 at an annual rate of 71 ml/year. This linear decline was not noticed in our study which may be the reflection of very high sugar levels at the diagnosis and eventual better control which is also reflected in asmall scale six years study by Ramiriez L.C. et al 17 (1991)

demonstrating that intensive treatment by subcutaneous insulin infusion improved both FVC & FEV1 percentage predictedvalues.
Recently Nakajima et al 18 reported reduced FVC and normal FEV1/FVC and concluded that impaired restrictive pulmonary function but not the obstructive pattern might be associated with metabolic disorders and metabolic syndrome in a severity dependant manner.

Conclusion:-
Lungs also bear the brunt of uncontrolled diabetes mellitus as evident by this study where mean reduction in FVC was 500ml and in FEV1 was 360 ml with the parameters showing a restrictive pattern. Thus lung is also a target organ for diabetes mellitus.

Limitation of the study:
The follow up period of the patient was short and so prolonged follow up is needed to further ascertain the effects of diabetics duration on the lung functions.

Future prospective:
All diabetics can be made to get a baseline pulmonary function test using spirometry with follow up spirometries as warranted.