| Background:Amyotrophic lateral sclerosis(ALS)is a neurodegenerative disorder involving both upper and lower motor neurons with an average survival time of 3 to 5 years.We do not yet fully understand the causes of the disease,nor the mechanisms for its progression.Respiratory deterioration is the main cause of ALS and affects almost all ALS patients in different courses.Pulmonary function tests(PFT)include forced vital capacity(FVC),vital capacity(VC),forced expired volume in one second(FEV1),peak expiratory flow(PEF)and Maximum Voluntary Ventilation(MVV),etc.,much applied in the clinical decision making.Currently,it is still controversial of the characteristics of respiratory deterioration in ALS patients,including the effect of the type of disease onset,as well as the progression rates.Moreover,number of study on the respiratory function characteristics in ALS patients based on Chinese population is limited.Objective:This study aimed at exploring the characteristics,risk factors and relation with prognosis of respiratory deterioration in ALS patients.Method:We performed a retrospective cohort study including 159 ALS patients at Peking Union Medical College Hospital from Jun 2014 to April 2017.Age at symptom onset,sex,time form onset to PFT,ALSFRS-R score,onset and area involved were recorded.All patients were followed in March 2016 and Jun 2017 separately.Depending on the pattern of onset,patents were subdivided into two groups.One included patients with bulbar-onset ALS and the other included those with limb-onset.In addition,patients with bulbar involvement till PFT were divided into one group,while those with limb-only involvement belonged to the other.Result:The mean age at symptom onset of 159 cases included was 52.9±10.1 years old;the male:female ratio was 1.24:1.Bulbar-onset of symptoms was seen in 17.0%patients,while 81.6%presented with limb-onset.The time from symptom onset to PFT was shorter in the bulbar-onset group(7.0 vs.11.5 m,p=0.004),as well as the time from symptom onset to diagnosis(8.0 vs.12.0m,p=0.027).47.4%cases showed bulbar involvement during the courses.Significant differences were showed of the age at symptom onset(p=0.025),time form symptom onset to diagnosis(p=0.026)and ALSFRS-R scores(p=0.004)between the two groups.The PFT parameters revealed a main characteristic restrictive type of dysfunction.Only 26.0%patients of respiratory dysfunction from PFT parameters had respiratory complaints.Mean FVC%,FEV1%and PEF%value was 86.7%±22.2%,85.6%±19.2%?83.2%±21.7%respectively.After adjusting for sex,ALSFRS-R score,time from symptom onset to diagnosis,BMI and age at symptom onset,no significant difference was observed for patients with time form symptom onset to PFT less than 14 mouths.In contrast,for those with time more than 14 mouth,bulbar-onset group showed worse PFT values than the limb-onset group,with differences was 27.5%(95%CI:4.3%,50.7%),24.7%(95%CI:4.3%,45.2%)and 42.0%(95%CI:17.7%,66.4%)separately.The decline rates for FVC%,FEV1%and PEF%were 0.7%per mouth,0.8%per mouth and 1.0%per mouth.No difference was found between bulbar and limb onset groups.?FVC%??FEV1%and ?PEF%of patients in bulbar-involved group were 1.5%(95%CI:0.0%-18.5%),1.4%(95%CI:0.0%-9.8%)and 1.8%(95%CI:0.0%-42.3%),which were significantly higher than those in limb-involved group of 0.2%(95%CI:0.0%-10.4%),0.5%(95%CI:0.0%-8.0%)and 0.4%(95%CI:0.0%-8.9%)(p<0.001,p<0.001 and p=0.003).The median survival time of our patients was 69.0 mouth.The prognostic was poor for patients with FVC%=<80%(HR=5.41).Other risk factors included age at symptom onset more than 55 years old(HR-2.62),higher ?FVC%(HR=1.25),?FEV1(HR= 1.45)and ?PEF%(HR=1.08).Conclusion:1)ALS patients with PFT abnormality might not show respiratory complain at the early period of the disease2)The main type of pulmonary dysfunction was restrictive pattern.3)Bulbar involvement predicted poorer respiratory function in ALS patients compared with limb-only involvement,no matter whether it was the bulbar-onset.4)The progression rate was higher in the bulbar involved patients than those with limb-only involvement.5)Risk factors for survival included respiratory dysfunction,higher progression rates of PFT values and later onset age. |
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