Table 3.

Positive Predictive Value and Relationship to the True Number of Fractures (N. 1564) with Different Reference Data in the National Patient Register (NPR)

	Reference Data from the NPR	Number of Registrations	Number of Actual Fractures	Erroneous Registrations	Positive Predictive Value (PPV) %	Confidence Interval (95%) of PPV	Relationship to the True Number of Fractures (%)
NPR	All registrations	2173	1513	660	69.6	67.7–71.6	138.9
	True number humeral fractures	1513	1513	0	100	100–100	96.7
	Number of patients (unique PINs)	1852	1513	339	81.7	79.9–83.5	118.4
	Adjusted registrations in the NPR*	1648	1513	135	91.8	90.5–93.1	105.4
SFR	All registrations	1375	1375	0	100	100–100	87.9

Note: *Adjustment algorithm used on NPR data for routine completeness calculations in the Swedish Fracture register.

Abbreviation: PIN, personal identification number.