Improve table with several multicolumns and multirows

Question

I've been working on a table with several multicolumns and multirows. Though the table is almost done, there are some details that I'm not very confortable. I don't think the last row Exarcebations requiring oral corticosteroids is really good.

Can someone help me doing it better? I would also like to separate the persistent columns though the last row wouldn't have separator.

 \documentclass[11pt,letterpaper,twoside,openright]{book}

 \usepackage{longtable}
 \usepackage{makecell} %used to insert break line inside table rows
 \usepackage{rotating}
 \usepackage{multirow} %tables with multirow


 \begin{document}

 \begin{sidewaystable}[htpb]
 \centering
 \resizebox{\columnwidth}{!}{%
    \begin{tabular}{l|c|c|ccc}
        \hline
        \multirow{3}{*}{Components of Severity} & \multirow{3}{*}{\thead{Age \\ (Years)}} & \multicolumn{4}{c}{Classification of Asthma Severity}\\
        \cline{3-6}
         & & \multirow{2}{*}{Intermittent} & \multicolumn{3}{c}{Persistent}\\
        \cline{4-6}
         & & & Mild & Moderate & Severe\\
        \hline
        \hline
        Symptoms & All & $\leq$ 2 days/week & > 2 days/week but not daily & Daily &     Throughout the day\\    
        \hline
        \multirow{2}{*}{Nighttime awakenings} 
            & 0–4 & 0 & 1–2x/month & 3–4x/month & > 1x/week\\   
            \cline{2-6}
            & $\geq$ 5 & $\leq$ 2x/month & 3–4x/month & > 1x/week but not nightly & Often 7x/week\\
        \hline
        \makecell[l]{SABA use\\ for symptom control} & All & $\leq$ 2 days/week & > 2 days/week but not daily & Daily & Several times a day\\
        \hline
        \makecell[l]{Interference \\with normal activity} & All & None & Minor limitation & Some limitation & Extremely limited\\   
        \hline
        Lung function & & & & &\\
        FEV1 (predicted) & $\geq$ 5 & \makecell{Normal FEV1 \\between exacerbations\\ > 80\%} & > 80\% & 60–80\% & < 60\%\\
        \hline
        \multirow{2}{*}{FEV1/FVC}
         & 5 – 11 & > 85\%  &   > 80\% & 75–80\% & < 60\%\\
         \cline{2-6}
         & $\geq$ 12 &  Normal & Normal & Reduced 5\% & Reduced > 5\%\\
         \hline
        \multirow{3}{*}{\makecell[l]{Exacerbations requiring \\oral corticosteroids}}
        & 0–4 & & \multicolumn{3}{c}{\makecell{$\geq$ 2x in 6 months \\or $\geq$ 4 wheezing episodes/year lasting > 1 day\\ AND risk factors for persistent asthma}}& &\\   
        %\cline{3-6}
        & 5-11 & & \multicolumn{3}{c}{$\geq$ 2x/year}& & \\
        & $\geq$ 12 & \multirow{-3}{*}{$\leq$ 1x/year} & \multicolumn{3}{c}{\makecell{Consider severity and interval since last exacerbation. \\Frequency and severity may fluctuate over time for patients in any severity category. \\ Relative annual risk of exacerbations may be related to FEV1.}}  && \\                   
\end{tabular}%
}
\end{sidewaystable}

\end{document}

Any ideas for improvement?

Thank you very much

Answer 1

I can propose this:

\documentclass[11pt,a4paper, twoside,openright]{book}%letterpaper,
\usepackage[utf8]{inputenc}
\usepackage[a4paper, margin = 1cm]{geometry}
\usepackage{longtable, booktabs}
\usepackage{makecell} %used to insert break line inside table rows
\renewcommand\cellalign{lc}
\renewcommand\theadfont{\normalsize\bfseries}
\setcellgapes{4pt}
\usepackage{rotating}
\usepackage{multirow} %tables with multirow
\usepackage{amsmath}
\usepackage{textcomp}
\newcommand × perweek{\texttimes/week}
\newcommand × permonth{\texttimes/month}
\newcommand × peryear{\texttimes/year}

\begin{document}

\begin{sidewaystable}[htpb]
  \centering
  \makegapedcells
  \begin{tabular}{l*{5}{c}}%{l|c|c|ccc}
    \toprule
    \multirowthead{8}[-2\cmidrulewidth]{Components of Severity} & \multirowthead{8}{Age \\ (Years)} & \multicolumn{4}{c}{\thead{Classification of Asthma Severity}}\\
    \cmidrule(lr){3-6}%[\dimexpr\cmidrulesep +\relax]
    & & \multirowthead{3}[\dimexpr0.5\cmidrulewidth-\cmidrulesep\relax]{Intermittent} & \multicolumn{3}{c}{\thead{Persistent}}\\
    \cmidrule(lr){4-6}
                              & & & Mild & Moderate & Severe \\
    \midrule
    \midrule
    Symptoms & All & $\leq$ 2 days/week & $ > 2 $ days/week but not daily & Daily & Throughout the day \\
    \cmidrule(lr){1-6}
    \multirow{2}{*}{Nighttime awakenings}
                              & 0–4 & 0 & 1–2 × permonth & 3–4 × permonth & $> 1$ × perweek \\
                              & $\geq 5$ & $\leq 2$ × permonth & 3–4 × permonth & $>1$ × perweek but not nightly & Often 7 × perweek \\
    \cmidrule(lr){1-6}
    \makecell[l]{SABA use & & & & & \\ for symptom control} & All & $\leq 2$ days/week & $ > 2 $ days/week but not daily & Daily & Several times a day\\
    \cmidrule(lr){1-6}
    \makecell[l]{Interference & & & & & \\with normal activity} & All & None & Minor limitation & Some limitation & Extremely limited\\
    \cmidrule(lr){1-6}
    Lung function & & & & & \\
    FEV1 (predicted) & $\geq 5$ & \makecell{Normal FEV1 & & & \\between exacerbations\\ $ > 80\,\% $} & $ > 80\,\% $ & 60–80\,\% & $ < 60\,\% $ \\
    \cmidrule(lr){1-6}
    \multirow{2}{*}{FEV1/FVC}
                              & 5–11 & $ > 85\,\% $ & $ > 80\,\% $ & 75–80\,\% & $ < 60\,\% $ \\
                              & $\geq 12$ & Normal & Normal & Reduced 5\,\% & Reduced $ > 5\,\% $ \\
    \cmidrule(lr){1-6}
    \multirowcell{6}{Exacerbations requiring \\oral corticosteroids}
    & 0–4 & & \multicolumn{3}{c}{\makecell{$\geq 2$\texttimes in 6 months \\or $\geq 4$ wheezing episodes/year lasting $ > 1$ day\\ AND risk factors for persistent asthma}} \\
    & 5–11 & & \multicolumn{3}{c}{$\geq 2$ × peryear} \\
    & $\geq 12$ & \multirow{-6}{*}{$\leq 1$ × peryear} & \multicolumn{3}{c}{\makecell{Consider severity and interval since last exacerbation. \\Frequency and severity may fluctuate over time for patients in any severity category. \\ Relative annual risk of exacerbations may be related to FEV1.}} \\
    \bottomrule
  \end{tabular}%
\end{sidewaystable}

\end{document}