Real World Health Care Data Analysis. Uwe Siebert

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Real World Health Care Data Analysis - Uwe Siebert


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use continued/started at this visitSatisfCareSatisfaction with Overall Fibro TreatmentSatisfMedSatisfaction with Prescribed MedicationPHQ8PHQ8 total scoreBPIPainBPI Pain scoreBPIInterfBPI Interference score

      For the REFLECTIONS simulated data set, simulation was performed separately for each treatment cohort. First, the original dataset was transformed from a vertical (one observation per patient per time-point) into a horizontal format (one record per patient). Next, a cohort-specific data set was created by random sampling (with replacement) from each original variable. The size of sample was 240, 140, and 620 for opioid, non-narcotic opioid, and other treatment cohort, respectively. The SAS/IML programming language was used to implement the Iman-Conover method following the code of Wicklin (2013) as shown in Program 3.1 using the sampled data (A) and the desired between variables rank-correlations (C).

      Program 3.1: Iman-Conover Method to Create a Simulated REFLECTIONS Data Set

      /* Use Iman-Conover method to generate MV data with known marginals

      and known rank correlation. */

      start ImanConoverTransform(Y, C);

      X = Y;

      N = nrow(X);

      R = J(N, ncol(X));

      /* compute scores of each column */

      do i = 1 to ncol(X);

      h = quantile(“Normal”, rank(X[,i])/(N+1));

      R[,i] = h;

      end;

      /* these matrices are transposes of those in Iman & Conover */

      Q = root(corr(R));

      P = root(C);

      S = solve(Q,P);

      M = R*S; /* M has rank correlation close to target C */

      /* reorder columns of X to have same ranks as M.

      In Iman-Conover (1982), the matrix is called R_B. */

      do i = 1 to ncol(M);

      rank = rank(M[,i]);

      tmp = X[,i];

      call sort(tmp);

      X[,i] = tmp[rank];

      end;

      return( X );

      finish;

      X = ImanConoverTransform(A, C);

      The three cohort-specific simulated matrices (X) were concatenated and then the dropout and missing data were imposed at random in order to reflect the amount of dropout/missingness observed in the actual REFLECTIONS data. Then the structure of the simulated data was converted from horizontal to back to vertical.

      The distributions of variables were almost identical for real and simulated data as displayed in Tables 3.3 and 3.4. This can be expected because the Iman-Conover algorithm simply rearranges the elements of columns of the data matrix. The descriptive statistics for real and simulated data are presented below.

      Table 3.3: Comparison of Actual and Simulated REFLECTIONS Data for One Observation per Patient Variables

realtype
realsimulated
AllN15751000
Cohort13.6514.00
NN opioidColPctN
opioidColPctN24.0024.00
otherColPctN62.3562.00
Gender94.5493.20
femaleColPctN
maleColPctN5.466.80
Race83.6282.30
CaucasianColPctN
OtherColPctN16.3817.70
Insurance78.1075.70
private/combinationColPctN
public/no insuranceColPctN21.9024.30
Doctor Specialty17.6517.60
Other SpecialtyColPctN
Primary CareColPctN15.8715.70
RheumatologyColPctN66.4866.70
Exercise10.0311.00
NoColPctN
YesColPctN89.9789.00
Inpatient hospitalization in last 12 months89.8490.70
NoColPctN
YesColPctN10.169.30
Other missed paid work to help your care in last 12 months77.7179.60
NoColPctN
YesColPctN22.2920.40
Have you used an unpaid caregiver in last 12 months62.8660.50
NoColPctN
YesColPctN37.1439.50
Have you hired a caregiver in last 12 months95.5695.70
NoColPctN
YesColPctN4.444.30
Have you received disability income in last 12 months70.8672.30
NoColPctN
YesColPctN29.1427.70
Age in yearsNMiss00
Mean50.4550.12
Std11.7111.56
BMI at BaselineNMiss00
Mean31.3031.36
Std7.347.01
Duration (in years) of symptomsNMiss216133
Mean10.2810.03
Std9.269.02
Time (in years) since initial DxNMiss216133
Mean5.735.29
Std6.276.05
Time (in years) since initial TrtmntNMiss216133
Mean5.225.26
Std6.026.18
PHQ 15 total score at BaselineNMiss00
Mean13.8114.03
Std4.644.79
FIQ Total Score at BaselineNMiss00
Mean54.5454.56
Std13.4313.47
GAD7 total score at BaselineNMiss00
Mean10.8110.64
Std5.775.67
MFI Physical Fatigue at BaselineNMiss00
Mean13.0913.00
Std2.282.17
MFI Mental Fatigue at BaselineNMiss00
Mean11.5111.52
Std2.382.49
CPFQ Total Score at BaselineNMiss00
Mean26.5126.62
Std6.446.43
ISIX total score at BaselineNMiss00
Mean17.6417.91
Std5.975.74
SDS total score at BaselineNMiss00
Mean18.2718.28
Std7.507.56

      Table 3.4: Comparison of Actual and Simulated REFLECTIONS Data for Visit-wise Variables

realtype
realsimulated
Visit15751000
1N
Opioids use76.0076.00
NoColPctN
YesColPctN24.0024.00
Satisfaction with Overall Fibro Treatment5.336.10
.ColPctN
1ColPctN12.1312.10
2ColPctN20.9519.70
3ColPctN25.2724.20
4ColPctN22.8624.30
5ColPctN13.4613.60
Satisfaction with Prescribed Medication10.039.80
.ColPctN
1ColPctN7.436.80
2ColPctN15.8115.60
3ColPctN31.6831.90
4ColPctN23.7524.30
5ColPctN11.3011.60
PHQ8
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