The Association between blood glucose and length of hospital stay due to Acute COPD exacerbation

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The Association between blood glucose and length
of hospital stay due to Acute COPD exacerbation

• Yusuf Kasirye, Melissa Simpson, Naren Epperla,
  Steven Yale

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Blood glucose and acute COPD exacerbations

• Introduction
• Methods
• Results
• Discussion

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Introduction

• Chronic Obstructive Pulmonary Disease (COPD) is
  the fourth most common cause of death in the
  United States, affecting 24 million people
• Several studies have looked at hospitalizations
  due to acute COPD exacerbations (AECOPD) and
  comorbidities such as diabetes mellitus and
  metabolic syndrome

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Introduction

• Two studies of hospital admissions found a
  marginal association between DM and length of
  hospital stay
• Did not examine blood glucose levels
• Another study found that increased blood glucose
  is associated with longer hospitalization
• Analyzed highest inpatient BG value only
• Looked at length of stay as lt9 days (good)
  compared to 9 days (bad)

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Introduction

• The purpose of this study is to examine the
  association between inpatient blood glucose (BG)
  levels and the following clinical outcomes in
  patients hospitalized for AECOPD
• In hospital complications
• Length of hospitalization
• Thirty day re-hospitalization (all cause)
• Ninety day mortality (all cause)

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Methods
Study population and design

• Retrospective cohort of 209 patients hospitalized
  for AECOPD (physician validated) from 1-1-24
  to 12-31-2008 at St. Josephs hospital
  (Marshfield WI)
• Inclusion criteria
• COPD diagnosis (according to GOLD criteria) at
  some point prior to index hospitalization
• AECOPD diagnosis at admission and discharge
• A BG measurement within 6 hours of
  hospitalization
• 2 BG measurements during hospitalization
  (analyzed both fasting and random blood glucose
  measurements)

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Methods
Outcomes

• In-hospital complications the presence of
  cardiac, respiratory, neurologic, renal, or
  septic complications during index hospitalization
  
• Length of hospital stay the time from admission
  until discharge from hospital, measured in days
• Thirty day readmission hospitalization for any
  cause within 30 days of the discharge date of
  index hospitalization
• Ninety day all cause mortality death due to any
  cause within 90 days of index hospitalization

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Methods
Statistical analysis

• Outcomes modeled as follows
• LOS analyzed both as a discrete and categorical
  (2 days vs. gt 2 days) outcome
• Thirty day readmission analyzed as a categorical
  outcome
• Ninety day all-cause mortality analyzed as a
  categorical outcome.
• Blood glucose was analyzed as a continuous
  variable and was calculated as mean per day
  (ng/ml), odds ratios reported for a 100 ng/ml
  decrease in BG
• Logistic regression analyses accounting for
  repeated BG measurement during hospitalization
  were used for odds ratio estimation (SAS, proc
  genmod, Cary NC)
• Age and DM were forced into adjusted models,
  other covariates were included if they had a
  significance level of 0.05 or changed the beta
  estimate for BG by 10

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Results
In-hospital complications
Complications during index hospitalization No Complications during index hospitalization Univariate analysis Univariate analysis Univariate analysis Adjusted analysis Adjusted analysis Adjusted analysis
Characteristic n 24 n 185 OR 95 CI p-value OR 95 CI p-value
Blood glucose (100 ng/ml decrease in daily mean)     1.81 0.81-4.05 0.15 1.81 0.95-3.47 0.07
Age (years) at hospital admission - mean (sd) 67.3(9.5) 64.5(8.1) 1.05 0.99-1.11 0.12 1.08 0.97-1.19 0.15
Diabetes Mellitus at hospital admission - n() 7(29) 56(30) 0.95 0..37-2.42 0.91 1.06 0.37-3.07 0.92
Male sex - n() 7(29) 73(39) 0.63 0.25-1.60 0.33
Corticosteroids given within 24 hours of hospitalization - n() 0(0) 176(96)
Current smoker - n() 75(41) 110(59) 0.73 0.30-1.80 0.50
Body mass index in kg/m2 - mean (sd) 32.6(8.7) 31.1(8.8) 1.02 0.97-1.07 0.45 1.08 1.01-1.16 0.02
Inhaled medications at the time of presentation - n() 20(83) 165(89) 0.61 0.19-1.95 0.40
History of chronic steroid use - n() 1(4) 21(11) 0.34 0.04-2.63 0.30
Received respiratory support during hospitalization - n() 5(21) 23(12) 0.54 0.18-1.59 0.26
Number of blood glucose measurements taken per day - mean (sd) 1.7(1.9) 2.6(1.8) 0.66 0.47-0.93 0.02      
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Results
LOS
Hospitalization 2 days Hospitalization gt 2 days Univariate analysis Univariate analysis Univariate analysis Adjusted analysis Adjusted analysis Adjusted analysis
Characteristic n 109 n 100 OR 95 CI p-value OR 95 CI p-value
Blood glucose (100 ng/ml decrease in daily mean)     1.44 1.01-2.04 0.04 1.58 1.09-2.29 0.01
Age (years) at hospital admission - mean (sd) 64.5(8.5) 65.2(8.1) 1.01 0.98-1.04 0.54 0.97 0.93-1.01 0.18
Diabetes Mellitus at hospital admission - n() 32(29) 31(31) 1.08 0.60-1.95 0.80 1.22 0.60-2.50 0.59
Received respiratory support during hospitalization - n() 22(18) 6(6) 3.96 0.53-10.23 0.005
Complications during hospitalization - n() 20(18) 4(4) 5.39 1.77-16.39 0.003
Male sex - n() 42(39) 38(38) 0.98 0.56-1.71 0.94
Corticosteroids given within 24 hours of hospitalization - n() 105(97) 95(95) 0.54 0.13-2.33 0.41
Current smoker - n() 37(34) 46(46) 1.66 0.95-2.90 0.08
Body mass index in kg/m2 - mean (sd) 31.4(9.4) 31.1(8.2) 1.00 0.97-1.03 0.80
Inhaled medications at the time of presentation - n() 98(90) 87(87) 0.75 0.32-1.76 0.51
History of chronic steroid use - n() 12(11) 10(10 0.91 0.37-2.21 0.83
Number of blood glucose measurements taken per day - mean (sd) 2.3(2.0) 2.7(1.6) 1.13 0.97-1.32 0.12      
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Results
LOS

• Unadjusted, BG modeled continuously was not
  associated with LOS (OR 1.25, 95 CI 0.87-1.81,
  p-value 0.22)
• Adjusting for age and DM, decreased BG was
  associated with a longer LOS (OR for 100 ng/ml
  decrease 1.39, 95 CI 1.04-1.87, p-value 0.03)

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Results
Thirty day readmission

• Thirty six people were readmitted within 30 days
  of discharge from index hospitalization
• BG was not associated with 30 day readmission
• Unadjusted OR 1.34, 95 CI 0.78-2.28, p-value
  0.29
• Adjusting for DM, age, and BMI 1.34, 95 CL
  0.75-2.41, p-value 0.33

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Results
Ninety day mortality

• Eight people died due to any cause within 90 days
  of index hospitalization
• BG was not associated with 90 day all cause
  mortality
• Unadjusted OR 2.68, 95 CI 0.92-7.79, p-value
  0.07
• Adjusting for DM, age, and BMI 1.93, 95 CL
  0.55-6.75, p-value 0.30

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Results
Mediation analysis

• Tested how much of the association between
  in-hospital complications and length of stay
  could be attributed to BG.
• Found that 4 of that association is due to BG (p
  0.07)

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Discussion

• Decreased BG has a marginal and weak association
  with in-hospital complications and longer LOS
• BG may be reflective of overall health in this
  population
• No association with 30 days readmission or 90 day
  all-cause mortality
• BG (as we measured it) probably of little
  prognostic utility in AECOPD patients

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Discussion

• Different than the study by Baker et al.
• May be due to difference in exposure and outcome
  definition
• Repeated their method on our data and found no
  association

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Discussion

• Future studies
• Employ continuous glucose monitoring to fully
  understand the complexities of corticosteroid
  usage, the glycemic response and clinical
  outcomes in this group of people
• Study the association between metabolic syndrome
  and clinical outcomes and how much glycemic
  status contributes to that association

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Disclosure

• The authors do not have conflicts of interest to
  report.
• This study was funded by a Marshfield Clinic
  Research Foundation resident research grant.