$query_handle->execute($patient_name);

##</code><code>##

use strict;
use warnings;
use DBI;

my $name = shift or die "need patient's name\n";

my $dbh = DBI->connect(
   'dbi:SQLite:dbname=foo.dbm',undef,undef,
   {RaiseError=>1}
);

my $sth = $dbh->prepare('
   SELECT name
   FROM patient_data
   WHERE name = ?
');

$sth->execute($name);

warn "no match for $name\n" unless $sth->rows;