1 Introduction
2 Materials and Methods
2.1 Variables Considered in the Study
2.2 Inferential Statistics
2.2.1 Methods of Statistical Analysis
2.2.2 Exploring Data Analysis
2.2.2.1 Compound Symmetry (CS) Covariance Models
2.2.2.2 Autoregressive Structure of order one [AR(1)] Covariance Models
2.2.2.3 Toeplitz (TOEP) Covariance Models
2.2.2.4 Unstructured (UN) Covariance Models
2.2.3 Transition Model
2.2.4 Methods of Parameter Estimation
2.2.5 Assumptions of Transition Model
3 Results and Discussion
3.1 Results
3.1.1 Descriptive Statistics Analysis
Variables | Minimum | Maximum | Mean | SD |
---|---|---|---|---|
Age | .17 | 5.00 | 2.0096 | 1.16726 |
MUAC status | 4.2 | 14.6 | 12.197 | .9015 |
Plump net | 15 | 90 | 36.78 | 13.740 |
Visits | Sex | Cough | Diarrhea | Fever | Residence | ART | |||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Male | Female | Yes | No | Yes | No | Yes | No | Urban | Rural | On | Pre | No | |
Visit 1 | 202 | 295 | 204 | 293 | 173 | 324 | 254 | 243 | 272 | 225 | 12 | 5 | 480 |
(%) | 40.64 | 59.36 | 41.46 | 58.95 | 34.81 | 65.19 | 51.11 | 48.89 | 54.73 | 45.27 | 2.41 | 1.01 | 96.58 |
Visit 2 | 202 | 295 | 204 | 293 | 173 | 324 | 254 | 243 | 272 | 225 | 12 | 5 | 480 |
(%) | 40.64 | 59.36 | 41.46 | 58.95 | 34.81 | 65.19 | 51.11 | 48.89 | 54.73 | 45.27 | 2.41 | 1.01 | 96.58 |
Visit 3 | 202 | 295 | 204 | 293 | 173 | 324 | 254 | 243 | 272 | 225 | 12 | 5 | 480 |
(%) | 40.64 | 59.36 | 41.46 | 58.95 | 34.81 | 65.19 | 51.11 | 48.89 | 54.73 | 45.27 | 2.41 | 1.01 | 96.58 |
Visit 4 | 202 | 295 | 204 | 293 | 173 | 324 | 254 | 243 | 272 | 225 | 12 | 5 | 480 |
(%) | 40.64 | 59.36 | 41.05 | 58.95 | 34.81 | 65.19 | 51.11 | 48.89 | 54.73 | 45.27 | 2.41 | 1.01 | 96.58 |
BMI | Sex | Cough | Diarrhea | Fever | Residence | ART | |||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Male | Female | Yes | No | Yes | No | Yes | No | Urban | Rural | On | Pre | No | |
Under | 565 | 767 | 541 | 791 | 479 | 853 | 667 | 665 | 743 | 589 | 33 | 18 | 1281 |
(%) | 69.93 | 65 | 66.3 | 67.49 | 69.22 | 65.82 | 65.59 | 68.79 | 68.35 | 65.37 | 68.75 | 90 | 66.72 |
Normal | 214 | 368 | 242 | 340 | 192 | 390 | 306 | 276 | 302 | 280 | 12 | 2 | 568 |
(%) | 26.49 | 31.19 | 29.66 | 29.01 | 27.75 | 30.09 | 30.09 | 28.42 | 27.78 | 31.08 | 25 | 10 | 29.58 |
Over | 16 | 34 | 19 | 31 | 16 | 34 | 29 | 21 | 26 | 24 | 3 | 0 | 47 |
(%) | 1.98 | 2.88 | 2.33 | 2.65 | 2.31 | 2.62 | 2.85 | 2.16 | 2.39 | 2.66 | 6.25 | 0 | 2.45 |
Obesity | 13 | 11 | 14 | 10 | 5 | 19 | 15 | 9 | 16 | 8 | 0 | 0 | 24 |
(%) | 1.61 | 0.93 | 1.72 | 0.85 | 0.72 | 1.47 | 1.47 | 0.93 | 1.47 | 0.89 | 0 | 0 | 1.25 |
Sub total | 808 | 1180 | 816 | 1172 | 692 | 1296 | 1017 | 971 | 1087 | 901 | 48 | 20 | 1920 |
(%) | 40.64 | 59.36 | 41.05 | 58.95 | 34.81 | 65.19 | 51.16 | 48.84 | 54.68 | 45.32 | 2.41 | 1.01 | 96.58 |
Time | Health Status | BMI | ||||
---|---|---|---|---|---|---|
Normal W. | Obesity | Over W. | Under W. | Mean | Variance | |
Time1 | 24 | 0 | 2 | 471 | 14 | 6.94 |
(%) | 4.12 | 0 | 4 | 35.36 | ||
Time2 | 179 | 1 | 6 | 311 | 17.19 | 11.53 |
(%) | 30.76 | 4.17 | 12 | 23.35 | ||
Time3 | 186 | 5 | 18 | 288 | 17.82 | 14.88 |
(%) | 31.96 | 20.83 | 36 | 21.22 | ||
Time4 | 193 | 18 | 24 | 262 | 18.81 | 24.69 |
(%) | 33.16 | 75 | 48 | 19.67 | ||
Sub total | 582 | 24 | 50 | 1332 | ||
(%) | 29.28 | 1.21 | 2.52 | 67 |
3.1.2 Explanatory Data Analysis
3.1.2.1 Individual Profile Plots
3.1.2.2 Exploring Mean Structure
3.1.2.3 Exploring Variance Structure
3.1.3 Checking Assumption for the Final Model
3.1.4 Assessing the Assumption on the Random Effects
3.1.5 First Order Transition Model
3.1.5.1 Random Effect Term Selection
Model | df | AIC | BIC | loglik test | L.ratio | p value | |
---|---|---|---|---|---|---|---|
Both | 1 | 19 | 9504.7 | 9505.1 | 9464.7 | 847.76 | < 0.0001 |
Slope | 2 | 19 | 9683 | 9685.3 | 9607.7 | ||
Intercept | 3 | 19 | 9640.8 | 9685.4 | 9640.8 |
3.1.5.2 Model Selection
3.1.5.3 Selecting Variance Function for FOTM
3.1.5.4 Selecting Correlation Structure Function
Fits | Model | Df | AIC | BIC | loglik | Test | L.Ratio | p value |
---|---|---|---|---|---|---|---|---|
Model. AR(1) | 1 | 19 | 10005.3 | 9997.3 | 9998.3 | |||
Model. CS | 2 | 19 | 10106.4 | 10094.4 | 10001.6 | |||
Model. Toep | 3 | 19 | 10013.7 | 10013.7 | 9993.6 | |||
Model. UN | 4 | 19 | 9504.7 | 9505.1 | 9464.7 | 4Vs3 | 847.76 | < 0.0001 |
Model | Df | AIC | BIC | loglik | Test | L.Ratio | p value | |
---|---|---|---|---|---|---|---|---|
Homoscedastic | 1 | 18 | 9684.8 | 9685.4 | 9640.8 | |||
Heteroscedastic | 2 | 19 | 9504.7 | 9505.1 | 9464.7 | 1Vs2 | 84.76 | < 0.0001 |
Random effects | SD | Corr |
---|---|---|
Intercept | 7.6189 | ICC |
time | 5.4086 | 0.635 |
Residual | 3.1071 |
Effect | Estimate | SE | DF | t-value | Pr > |t| | 95% CI |
---|---|---|---|---|---|---|
Intercept | 21.5009 | 2.0271 | 924 | 10.61 | .* | (20.9162, 21.7403) |
Sex Female | 0.6582 | 0.7752 | 924 | 0.85 | 0.3961 | (− 0.0019, 0.7093) |
Cough No | − 0.4436 | 0.3260 | 924 | − 1.36 | 0.1739 | (− 0.5012, 0.0019) |
Diarrhea No | 0.3508 | 0.3774 | 924 | 0.93 | 0.0328* | (0.2901, 0.3975) |
Fever No | − 0.1801 | 0.3116 | 924 | − 0.58 | 0.5634 | (− 0.1008, 0.0016) |
ART on ART | − 2.5234 | 1.1038 | 924 | − 2.29 | 0.0225* | (− 2.6074, − 2.4301) |
ART On pre-ART | − 5.8898 | 1.8288 | 924 | − 3.22 | 0.0013* | (− 5.9910, − 5.5001) |
RES Rural | − 0.4925 | 0.3237 | 924 | 1.52 | 0.0128* | (− 0.5010, − 0.4091) |
Age | − 0.1009 | 0.0266 | 924 | − 3.79 | 0.0002* | (− 0.2010, − 0.0101) |
MUAC | − 0.0885 | 0.1085 | 924 | − 0.82 | 0.4145 | (− 0.0991, 0.0001) |
PN | 0.0550 | 0.0292 | 924 | 1.88 | 0.0401* | (0.0367, 0.0812) |
Time | − 0.2628 | 0.5518 | 924 | − 0.48 | 0.0234* | (− 0.3615, − 0.1567) |
PN*Time | 0.0069 | 0.01012 | 924 | − 0.69 | 0.0391* | (0.0032, 0.0081) |
Time*Sex Female | − 0.12174 | 0.4477 | 924 | − 0.27 | 0.7858 | (− 0.21674, 0.00119) |
MUAC*Time | 0.04240 | 0.03211 | 924 | 1.32 | 0.0471* | (0.02420, 0.06147) |
Age*Time | 0.008248 | 0.008716 | 924 | 0.95 | 0.0344* | (0.005919, 0.010991) |
PN*Time*Sex Female | 0.00016 | 0.006926 | 924 | − 0.02 | 0.0491* | (0.00009, 0.00189) |
Diarrhea*Time*RER | − 1.9287 | 0.6456 | 924 | − 2.71 | 0.0251* | (− 2.0001, − 1.9987) |
bmi_1 | 0.0143 | 0.0181 | 924 | − 0.79 | 0.0427* | (0.0034, 0.0267) |
Effect | Num.DF | Den.DF | F-value | Pr > |F| |
---|---|---|---|---|
Sex | 1 | 924 | 0.72 | 0.3961 |
Cough | 1 | 924 | 1.85 | 0.1739 |
Diarrhea | 1 | 924 | 0.86 | 0.0328* |
Fever | 1 | 924 | 0.33 | 0.5634 |
ART | 2 | 924 | 5.32 | 0.0051* |
RES | 1 | 924 | 2.31 | 0.0128* |
Age | 1 | 924 | 14.33 | 0.0002* |
MUAC | 1 | 924 | 0.67 | 0.4145 |
PN | 1 | 924 | 3.54 | 0.0401* |
Time | 1 | 924 | 0.44 | 0.0234* |
PN*Time | 1 | 924 | 0.60 | 0.0391* |
Time*Sex | 1 | 924 | 0.07 | 0.7858 |
MUAC*Time | 1 | 924 | 1.74 | 0.0471* |
Age*Time | 1 | 924 | 0.90 | 0.0344* |
PN*Time*Sex | 1 | 924 | 0.00 | 0.0491* |
Diarrhea*time*RER | 1 | 924 | 0.36 | 0.0251* |
bmi_1 | 1 | 924 | 0.63 | 0.0427* |