# Adaptive Stacking Ensemble Techniques for Early Severity Classification of COVID-19 Patients
## 3 Proposed Method
### Preprocessing
\begin{table}
\begin{tabular}{c c c c c c} \hline
**Clinical Variables** & **Type** & \multicolumn{2}{c}{**Components**} & **Patient (or = 5644)** & **Missing Values** \\ \hline  & & \multicolumn{4}{c}{**Patient Demographics**} \\  & & (1) & 0–9 years & 66 (1.17\%) & \\  & & (2) & 10–19 years & 205 (3.63\%) & \\  & & (3) & 20–29 years & 1110 (19.67\%) & \\ _AGE_ & 9 categories & (4) & 30–39 years & 566 (10.03\%) & \\ _(Years)_ & 9 categories & (5) & 40–49 years & 740 (13.11\%) & 0 (0\%) \\  & & (6) & 50–59 years & 1149 (20.36\%) & \\  & & (7) & 60–69 years & 920 (16.30\%) & \\  & & (8) & 70–79 years & 554 (9.82\%) & \\  & & (9) & Over 80 years & 334 (5.92\%) & \\ \hline _SEX_ & & (1) & Male & 2333 (41.34\%) & \\ _(Gender)_ & 2 categories & (2) & Female & 3311 (58.66\%) & 0 (0\%) \\ \hline _PREG_ & \multirow{2}{*}{2 categories} & (1) & Yes & 19 (0.34\%) & \\ _(Pregnancy)_ & & (2) & No & 3276 (58.04\%) & 2349 (41.62\%) \\ \hline \multirow{4}{*}{_PREGW_ (_Pregnancy Week_)} & \multirow{4}{*}{5 categories} & (1) & 0 weeks & 50 (0.89\%) & \\  & & (2) & 1–9 weeks & 26 (0.46\%) & \\ \cline{1-1}  & & (3) & 10–19 weeks & 8 (0.14\%) & \\ \cline{1-1}  & & (4) & 20–29 weeks & 4 (0.07\%) & \\ \hline \multirow{4}{*}{_BMI_ (_Body Mass Index_)} & \multirow{4}{*}{4 categories} & (1) & Less than 18.5 (underweight) & 260 (4.61\%) & \\  & & (2) & 18.5–24.9 (normal) & 2919 (51.72\%) & \\ \cline{1-1}  & & (3) & 25.0–29.9 (overweight) & 1061 (18.80\%) & \\ \cline{1-1}  & & (4) & Greater than 30 (obese) & 210 (3.72\%) & \\ \hline \multirow{4}{*}{_SBP_ (_Systelic Blood Pressure_)} & \multirow{4}{*}{5 categories} & (1) & Less than 120 & 1317 (23.33\%) & \\  & & (2) & 120–129 & 1145 (20.29\%) & \\ \cline{1-1}  & & (3) & 130–139 & 1092 (19.35\%) & \\ \cline{1-1}  & & (4) & 140–159 & 1433 (25.39\%) & \\ \cline{1-1}  & & (5) & Greater than 160 & 522 (9.25\%) & \\ \hline \multirow{4}{*}{_DBP_ (_Dinastolic Blood Pressure_)} & \multirow{4}{*}{5 categories} & (1) & Less than 80 & 2131 (37.76\%) & \\  & & (2) & 80–89 & 1808 (32.03\%) & \\ \cline{1-1}  & & (3) & 90–99 & 1061 (18.80\%) & \\ \cline{1-1}  & & (4) & Greater than 100 & 509 (9.02\%) & \\ \hline \multirow{4}{*}{_HRI_ (_Heart Rate_)} & \multirow{4}{*}{Numeric} & (1) & Less than 60 (bradycardia) & 167 (2.96\%) & \\  & & (2) & 120–129 (normal) & 4521 (80.10\%) & \\ \cline{1-1}  & & (3) & 130–139 (tachycardia) & 834 (14.78\%) & \\ \hline \multirow{4}{*}{_TEMPI_ (_Temperature_)} & \multirow{4}{*}{Numeric} & (1) & Less than 37.5 \({}^{\circ}\)C & 4925 (87.26\%) & \\  & & (2) & 37.5–37.9 \({}^{\circ}\)C & 471 (8.35\%) & \\ \cline{1-1}  & & (3) & 38–38.4 \({}^{\circ}\)C & 137 (2.43\%) & \\ \cline{1-1}  & & (4) & Greater than 38.4 \({}^{\circ}\)C & 74 (1.31\%) & \\ \hline \multicolumn{4}{c}{**Symptoms**} \\ _FEVER_ & \multirow{2}{*}{2 categories} & (1) & Yes & 1339 (23.72\%) & \\  & & (2) & No & 4301 (76.20\%) & 4 (0.07\%) \\ \hline _COUGH_ & \multirow{2}{*}{2 categories} & (1) & Yes & 2354 (41.71\%) & \\  & & (2) & No & 3286 (58.22\%) & 4 (0.07\%) \\ \hline _SPITUM_ & \multirow{2}{*}{2 categories} & (1) & Yes & 1629 (28.86\%) & \\  & & (2) & No & 4011 (71.07\%) & 4 (0.07\%) \\ \hline _ST_ & \multirow{2}{*}{2 categories} & (1) & Yes & 879 (15.57\%) & \\ _(Sore Threat)_ & & (2) & No & 4761 (84.36\%) & 4 (0.07\%) \\ \hline _RRR_ & \multirow{2}{*}{2 categories} & (1) & Yes & 618 (10.95\%) & \\ _(Rummy Nose)_ & & (2) & No & 5022 (88.98\%) & 4 (0.07\%) \\ \hline _MAM_ & \multirow{2}{*}{2 categories} & (1) & Yes & 923 (16.35\%) & \\ _(Muscle Aches)_ & & (2) & No & 4717 (83.58\%) & 4 (0.07\%) \\ \hline _FM_ & \multirow{2}{*}{2 categories} & (1) & Yes & 242 (4.29\%) & \\ _(Fatigue)_ & & (2) & No & 5398 (95.64\%) & 4 (0.07\%) \\ \hline _SOB_ & \multirow{2}{*}{2 categories} & (1) & Yes & 700 (12.40\%) & \\ _(Shortness of Bratt)_ & & (2) & No & 44940 (87.53\%) & 4 (0.07\%) \\ \hline _HEADA_ & \multirow{2}{*}{2 categories} & (1) & Yes & 964 (17.08\%) & \\ _(Handache)_ & & (2) & No & 4676 (82.85\%) & 4 (0.07\%) \\ \hline \end{tabular}
\end{table} 
Table 1: Clinical variables of COVID-19 patient dataset.