The missing PDO::PARAM_DOUBLE actually leads to very annoying problems.

SQLite considers a NUMERIC to be always less than a TEXT or REAL.
So string '1' is not less than double 1.1.

The following unparameterized statement shows this behaviour:
$rs = $sqlite->prepare('SELECT '1' < 1.1 as "result"');
$stmt->execute();
$rs = $stmt->fetch();
$stmt->closeCursor();
print_r($rs['result']); // 0 works as expected (and the same way as SQLite CLI.)

Now we try to perform the same operation using a parameterized statement:
$stmt = $sqlite->prepare('SELECT :left < :right as "result"');

Option A. Binding double as string:
$stmt->bindValue(':left', '1', PDO::PARAM_STR); 
$stmt->bindValue(':right', 1.1, PDO::PARAM_STR); 
$stmt->execute();
$rs = $stmt->fetch();
$stmt->closeCursor();
print_r($rs['result']); // 1 failure.  

Option B. Binding double as integer:
$stmt->bindValue(':left', '1', PDO::PARAM_STR); 
$stmt->bindValue(':right', 1.1, PDO::PARAM_INT);
$stmt->execute();
$rs = $stmt->fetch();
$stmt->closeCursor();
print_r($rs['result']); // 0 Seems to work, but ...

... this way we cannot tell double from integer. SQLite would consider
integer 1 to be less than double 1.1. 
$stmt->bindValue(':left', 1, PDO::PARAM_INT); 
$stmt->bindValue(':right', 1.1, PDO::PARAM_INT);
$stmt->execute();
$rs = $stmt->fetch();
$stmt->closeCursor();
print_r($rs['result']); // 0 Failure

So there is no way with PDO to correctly parameterize double values. 
I request to provide PDO::PARAM_DOUBLE.

+1, this is a really annoying issue, and the only way to circumvent it is to walk manually through every result set and cast to float every value. I can't believe there has been no activity on this for almost 4 years