Passing in a shell variable to AWK program used as a match pattern

I have a need to get the backlog message of a shareplex replicaton queue based on the queue name, I am not aware that there is a simple command in SharePlex to do it. So I developed a script. I have learned how to pass in a shell variable to the AWK program. This variable will thus be used as a match pattern in the AWK program.

The outoput of the SharePlex command I know to show the backlog messages looks like:

$ sp_ctrl qstatus on myhostname

Queues Statistics for myhostname
  Name:  QueueD (o.prddb-o.rptdb) (MTPost queue)
    Number of messages:      11825 (Age         7 min; Size      21547 mb)
    Backlog (messages):        126 (Age         0 min)

  Name:  QueueA (o.prddb-o.rptdb) (MTPost queue)
    Number of messages:     809345 (Age        48 min; Size     414840 mb)
    Backlog (messages):     806421 (Age        44 min)

  Name:  QueueB (o.prddb-o.rptdb) (MTPost queue)
    Number of messages:      49512 (Age       158 min; Size      71059 mb)
    Backlog (messages):      14425 (Age         4 min)

  Name:  QueueC (o.prddb-o.rptdb) (MTPost queue)
    Number of messages:       9678 (Age         8 min; Size     129632 mb)
    Backlog (messages):        155 (Age         0 min)

  Name:  QueueE (o.prddb-o.rptdb) (MTPost queue)
    Number of messages:          2 (Age         0 min; Size      28042 mb)
    Backlog (messages):          0 (Age         0 min)

My script:

----- script backlog_q.sh -------
#!/bin/ksh
# script bakclog_q.sh
# display backlog of a queuue

qname="QueueB"
sp_ctrl qstatus on myhostname  /usr/xpg4/bin/awk -v pat="$qname" '
begin
{
   if ( $0 ~ pat ) {
     getline
     getline
     print $3
   }
}'  read backlog

echo $backlog

---- end of the script --------