title: [The characteristics and clinical manifestation of subjects with non-specific pattern of pulmonary function tests].
abstract: OBJECTIVE
  To analyze the characteristics of pulmonary function and the clinical significance of non-specific pattern (NSP).
  
  
  METHODS
  A total of 1933 pulmonary function tests of adult patients were analyzed, and those with NSP were selected. The pulmonary function test results, clinical diagnosis and radiological manifestations were analyzed. Normal distribution data were compared by t test, while non-normal distribution data were compared by Mann-Whitney U test, and χ(2) test was used to compare ratios.
  
  
  RESULTS
  There were 61 patients in the NSP group and 1017 in the control group. The BMI of the 2 groups was (24.5 ± 4.6) and (24.5 ± 3.8) kg/m(2), respectively, being not significantly different (t = 0.008, P > 0.05). The age was 64 (49-74) years and 56 (42-70) years, and the smoking index was 0.4 (0-20) and 0 (0-10), respectively, showing no significant differences (Z values were -2.209 and -2.571, respectively, all P < 0.05). In the NSP group, FEV1 was 69% (66%-73%) predicted, FVC 75% (70%-77%) predicted, FEV1/FVC 75% (73%-78%), RV 118% (105%-145%) predicted, and TLC 86% (82%- 93%) predicted, which were significantly different as compared to those of the control group [95% (87%-104%), 98% (90%-106%), 79% (76%-84%), 101% (88%-114%) and 94% (88%-102%), respectively],(Z values are -13.059--5.185, all P < 0.05). RV/TLC was (52 ± 11)% in the NSP group and (39 ± 9)% in the control group, the difference being significant (t = -10.351, P < 0.05). The decreased TLC indicated restricted ventilation, while the increased RV and RV/TLC indicated air trapping. The clinical diagnosis of NSP included obstructive and restrictive diseases, some of which showed severe radiological abnormalities, but there were 31 patients without pulmonary lesions.
  
  
  CONCLUSIONS
  Age and smoking, but not obesity, may play a role in NSP.NSP has characteristics of obstructive and restrictive ventilation defects, but does not associate with particular diseases, thus having limited clinical significance.
authors: Department of Respiratory and Critical Care Medicine, Peking University People's Hospital, Beijing 100044, China.
authors: De-xun
authors: DX
authors: Zhou
authors: Department of Respiratory and Critical Care Medicine, Peking University People's Hospital, Beijing 100044, China.
authors: Jing-an
authors: JA
authors: Wei
authors: Department of Respiratory and Critical Care Medicine, Peking University People's Hospital, Beijing 100044, China.
authors: Qing
authors: Q
authors: Chen
authors: Department of Respiratory and Critical Care Medicine, Peking University People's Hospital, Beijing 100044, China.
authors: Jun
authors: J
authors: Gai
authors: Department of Respiratory and Critical Care Medicine, Peking University People's Hospital, Beijing 100044, China.
authors: Yan-wen
authors: YW
authors: Chen
authors: Department of Respiratory and Critical Care Medicine, Peking University People's Hospital, Beijing 100044, China. Email: gaozhancheng5446@163.com.
authors: Zhan-cheng
authors: ZC
authors: Gao
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000465:Algorithms; D015992:Body Mass Index; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D017563:Lung Diseases, Interstitial / Q000175:diagnosis / Q000503:physiopathology; D008173:Lung Diseases, Obstructive / Q000175:diagnosis* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D012129:Respiratory Function Tests; D012189:Retrospective Studies; D012907:Smoking / Q000503:physiopathology; D014797:Vital Capacity / Q000502:physiology